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Johnson 120 annoyances..


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05-04-10, 11:23 AM   #1  
Johnson 120 annoyances..

I have a '94 Johnson 120 (J120TLARK) with a few.. annoyances. First, It's got a backfire at low throttle speeds.. (idle - 2000rpms or so) Usually, after it is warmed up and has ran WOT (or just under) it doesnt do it as much. After running no-wake speeds for awhile, it will start backfiring (and loading up). It doesnt do it constantly, and after planing back out it will clean out and run up just fine. I put a new set of NGK BZHS-10 plugs in it gapped at .035" and this is what they look like:
Port side (cyl 2 & 4)

Stbd side (cyl 1 & 3)


I've been told this is somewhat normal for the "loopers" but it seems excessive to me, and I am a tad leary of doing any carb. adjustments without all of the proper tools. I did check the timing, which is supposed to be 6*ATDC and ended up being 9-10* ATDC I think.

Second, Is this normal? Ever since I got this boat, The transom was a little saggy (rotted. )and thus having to trim the engine all the way up to get max speed . I have since replaced the transom and no longer have the sag, but can't trim it up very much before it loses its bite.. here's where I put it to get on plane:

And this is about as high as I can go now.


In the Top picture, I can go down a little bit more from there and the highest the engine will go is the second tick mark above the middle of the gauge. (while above 3000rpms - safety feature I think...?) I'm guessing its normal, I am just not used to the engine being where its supposed to be on a straight transom.. I'm using a 13 7/8" x 19P SST prop. WOT is about 5800rpm.

Sorry for the ridiculously long post.. Thanks in advance.
Tim

 
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05-04-10, 12:50 PM   #2  
Without knowing how the Johnson carb is set up, it sure looks like heavy flooding. If the carb has a float, that is where I would check first. Either the float has absorbed fuel or the float valve is sticking.


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05-04-10, 02:43 PM   #3  
Posted By: goldstar Without knowing how the Johnson carb is set up, it sure looks like heavy flooding. If the carb has a float, that is where I would check first. Either the float has absorbed fuel or the float valve is sticking.
Well, based on information I've gotten from other people, the VRO is a little oil happy but that shouldn't cause it to backfire. It does smoke a bit when you start it up, but once you run it and warm it up, that goes away for the most part. I know the high-speed mixture is metered by a jet and the low-speed mixture has an adjustment screw.. I thought about leaning the idle mix down a little bit.. would that help?

The carbs were rebuilt 2 years ago and has been stored over winter with Sta-bil and Seafoam in the gas since I bought the boat 3 years ago.
(rebuild kits come with new o-rings, gaskets, and a float.)

edit: This thing has 4 carbs - 2 per intake manifold..

 
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05-04-10, 05:54 PM   #4  
I mistyped the timing - it is supposed to be 18* BTDC according to the sticker on the air box. When I checked the timing last, it was a few degrees less.. 15 or 16*. My memory is a little fuzzy, but I went and looked at it to verify.

Also, I checked the pulse limiter fitting and cleaned it out with carb spray per the shop manual. Is that pulse limiter supposed to be free flowing from both sides of the fitting? Mine allows air to pass from either side of fitting. I looked inside the fitting hole on the engine and I saw no carbon build up, so it appears to be working properly. I'm guessing the backfire has to be ignition related and there's something amiss with the fuel system causing the rich condition.. Anyone have any thoughts?

 
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05-04-10, 08:19 PM   #5  
Ok I will see if I can get this in one post but If I miss something post back.

As far as the back fire check idle timing, there should be a separate adjustment for that. The pulse limiter will be free flowing each way, it is used to limit the backpressure during a backfire. Also try champion spark plugs, omc's seam to like them better than the ngk.

Have you checked compression?

Also try a low ash oil brp's xd50 is real good and has detergents in it to help with carbon build up. Also something to try is to decarbon it with engine tuner, it's sold at any marine shop.

What hole is the motor mounted on? can it be lowered 1 hole? This should help with getting on plane. 5800 rpm's is about perfect for top rpm.

I hope this helps if not post back and I will be back tomorrow night.

 
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05-05-10, 01:04 PM   #6  
Posted By: samuari Ok I will see if I can get this in one post but If I miss something post back.

As far as the back fire check idle timing, there should be a separate adjustment for that. The pulse limiter will be free flowing each way, it is used to limit the backpressure during a backfire. Also try champion spark plugs, omc's seam to like them better than the ngk.

Have you checked compression?

Also try a low ash oil brp's xd50 is real good and has detergents in it to help with carbon build up. Also something to try is to decarbon it with engine tuner, it's sold at any marine shop.

What hole is the motor mounted on? can it be lowered 1 hole? This should help with getting on plane. 5800 rpm's is about perfect for top rpm.

I hope this helps if not post back and I will be back tomorrow night.
I forgot to mention this is on an Alumacraft Competitor 185cs boat, and the engine is as low as it can go.

I already ordered some Champion plugs - should be in tomorrow. Those NGK's in the pictures have about 7 gallons of gas on them. I ordered 4 QL78YC and 4 QL82YC Champ's - I get stuck with a fair amount of no-wake zones on the river so I was going to try the hotter plug if the other one fouls. I am going to De-carbon w/ Seafoam this weekend and put new plugs in. I've been using Amsoil HP synthetic Injector oil for the last year.

Worst case scenario, if these things don't work, I'm going to replace the VRO pump too. I am unsure of its age and I know it hasnt been replaced since I bought it. I was quoted $397 for the VRO pump.

 
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05-05-10, 01:13 PM   #7  
Posted By: samuari Ok I will see if I can get this in one post but If I miss something post back.

As far as the back fire check idle timing, there should be a separate adjustment for that.
I tried adjusting this according to my clymer shop manual and it seemed to make the idle better but made it doggy. If I backed the timing off a few degrees it seemed to make the idle okay most of the time and would let it run up better. Is there another way of doing it? The sticker says "18* BTC" so I'm just assuming thats Before TDC. I was adjusting the slotted screw under the flywheel on the right side (looking at it from the front of the engine)

 
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05-05-10, 07:02 PM   #8  
18 degrees BTC is surely "before" top center. I am following this thread because I'm having similar problems with my old Merc 850. Going to hotter plugs helped some, but didn't make the "loading up" problem go completely away. It seemed to be down on power and the hotter plugs hasn't changed that either. I'm at a loss for what to do also... Good luck with your unit.

 
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05-05-10, 07:46 PM   #9  
I am a huge fan of engine tuner rather than sea foam, I might be wrong but I think it works a lot better. I think that will make a big difference.

 
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05-05-10, 08:03 PM   #10  
Posted By: samuari I am a huge fan of engine tuner rather than sea foam, I might be wrong but I think it works a lot better. I think that will make a big difference.
Well, from other threads on iboats.com, most people said they had very similar results with seafoam vs. the oem engine de-gunkers.. Plus its cheaper and more readily available. I am going to try the seafoam first, change plugs and see how it runs. I will probably pull the heads off and look at the inside of the cylinders/pistons and see whats left after that. If everything doesnt come out, I'll do the OEM route and use their engine cleaner. At this time, this is what I can afford to do and still keep the engine running well enough to get out and enjoy it. If the backfire still exists after getting the plugs burning right, I will then go to doing adjustments to the timing and go from there. I have the BZ7HS-10 (QL77JC4 equivalent) plugs in it now, I got 4 of the hotter Champ QL78YC plugs and the hotter yet Champ QL82YC plugs to try. I got these Champs for a steal, too. $1.99 each. List price was almost $7 with a retail at about $4 I paid $3.40 a plug for the BZ7HS-10's so the champs are actually more expensive (every other parts store I called)which I find really odd. Nonetheless, I'm going to track down a small marine gas can to use to do the de-gunking on saturday and do a little test-n-tune on the water saturday sometime.

 
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05-05-10, 08:12 PM   #11  
Posted By: rebel63 18 degrees BTC is surely "before" top center. I am following this thread because I'm having similar problems with my old Merc 850. Going to hotter plugs helped some, but didn't make the "loading up" problem go completely away. It seemed to be down on power and the hotter plugs hasn't changed that either. I'm at a loss for what to do also... Good luck with your unit.
I think all 2 stroke outboards have a tendency to load up under extended trolling/no wake speeds. I would assume you need to step up the heat range again on your plugs. I remember my old autoshop teacher from high school had said if you're going to change heat ranges, go two steps hotter since there isnt a significant difference from one to the next hotter/colder respectively. Spark plug gap could have a lot to do with it too. From what I've been reading, going with a wider gap (in my instance, .010" bigger) will give a better idle. It may not curb the loading up, but if the plugs are burning hotter it should help it clean out a lot faster. I've ran this boat/motor for the past 3 years and its at least been consistent. It runs pretty well when the water temp is over 80*, but in cooler water temps, it loads up more and backfires more. BUT the key difference is I had a few morons cross-referencing the WRONG plugs. for 2 of the last 3 years I was running (my stupidity) standard resistor plugs instead of the proper inductive resistor plugs. The engine starts better with these, but its nowhere near hot enough to burn the crud off. If anyone else wants to weigh in, please do so. I will read and learn and do some testing on Saturday.

 
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05-05-10, 08:15 PM   #12  
Sounds good.

I'm not sure what the instructions are for the sea foam but what I do is get the motor hot, run it on the mixture for a couple minutes at high idle then put it into the engine strong enough to kill the engine try and restart and put some more in. Let is set overnight and run it till it gets hot again and see how it runs. I will do this twice if I see a lot of carbon coming out of the prop area.
You should do this with old spark plugs and put new ones in after, it will fowl them out.

Good luck, I hope this helps.

 
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05-05-10, 08:18 PM   #13  
Another thing to look at is if the thermostats are working properly. If they stick open it could be running too cold and load up. Cylinder head temp should be over 120.

 
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05-05-10, 08:27 PM   #14  
Posted By: samuari Sounds good.

I'm not sure what the instructions are for the sea foam but what I do is get the motor hot, run it on the mixture for a couple minutes at high idle then put it into the engine strong enough to kill the engine try and restart and put some more in. Let is set overnight and run it till it gets hot again and see how it runs. I will do this twice if I see a lot of carbon coming out of the prop area.
You should do this with old spark plugs and put new ones in after, it will fowl them out.

Good luck, I hope this helps.
They had said to do it this way: While on the water, have about 3/4-1gal fresh gas and mix in a whole can of sea foam. With the engine warmed up, run this mixture on moderate idle speed to get the stuff into the engine and smoking some. Shut down for 15-20 minutes, and repeat. They recommended doing this 3 times (which should use up most of the fuel mixture) with the second and third times running to higher throttles (half and even WOT) to get more of the junk out. I know the tops of the pistons are carboned up but I dont think the rings are sticking. I will do a compression test after the de-gunking and see what I get. I just dont have a compression tester and cant afford to buy one right now.

Posted By: samuari Another thing to look at is if the thermostats are working properly. If they stick open it could be running too cold and load up. Cylinder head temp should be over 120.
The Thermostats are new. I replaced them a year ago as I thought the engine was overheating. (which it wasn't, it was the low oil warning tripping instead.. didnt know what the different tones meant at the time) I will find a way to check the cyl. head temps - I know they're over 120 and under 173.

 
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05-07-10, 05:51 PM   #15  
I borrowed an old (metal) 3gal marine gas tank to use to mix fuel to De-Carbon my engine tomorrow. Being that its old, its got a little rust inside the tank.. some loose and some just stuck to the inside of the tank. I was going to get all of the loose junk out and rinse out as much of the residue as I can - is it a big deal if there are still chunks floating around? I pulled the pickup tube/fitting and checked the screen - it has no holes and is clean as a whistle. I would assume it should be fine to mix 1 gallon of gas in, right? The engine has a fuel filter just before the VRO pump, too.

 
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05-07-10, 07:34 PM   #16  
I would try to find another tank, but if that's not possible put another filer before your motor. You don't need to add to your problems.

Are you sure your going out tomorrow? A snowmobile might be better suited for the temperatures we're having

 
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05-07-10, 07:49 PM   #17  
Posted By: samuari I would try to find another tank, but if that's not possible put another filer before your motor. You don't need to add to your problems.

Are you sure your going out tomorrow? A snowmobile might be better suited for the temperatures we're having
I was thinking of adding another filter. I would buy my own tank if I had the money, but I'm broke as a joke. Not to mention, I will only use it once or twice and its just not worth it. I'd be better off with a regular gas can with a hose in it.. This isn't the ideal scenario, but it'll have to work.. I could grab a 5gal OMC tank thats in a little better shape, but I dont have the connector for the tank.

Its supposed to be 54 tomorrow. I want to get the motor squared up before I take it up to Lake Vermilion in early June. The oily plugs, backfiring, and ridiculous amount of smoke is driving me nuts.. not to mention its not the most friendly on gas, either. I'm arming myself with a timing light, fresh gas, and spark plugs..

 
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05-08-10, 11:01 AM   #18  
Well, I am going to head out to try to tune up the ol' beast. My plan of attack is to first try to loosen all of the carbon up. After that is done, I'm going to change plugs over to the QL78's and check idle and WOT timing. After this is adjusted (if needed), I'm going to check plugs. If they are blackened again, I'm going to pop the QL82's in and run again. If the Decarb doesnt get it all, I'll run a can of Engine Tuner next week and check again. If all of this doesnt do the trick, Carb rebuilds are in order. I did a compression check 2 or 3 years ago and yielded 110-120psi. Before taking the carbs out, I will do another Comp. test. If everything checks out and is adjusted properly and I still have lots of smoke, black plugs, and backfiring, then the VRO probably needs to be changed... right? What about idle mixture? Based on my small engine knowledge, I would assume if the idle mix is too rich, it'd smoke a lot and foul plugs.. perhaps I'll mess around this this a bit too if I have time (and am not totally frozen)..

 
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05-08-10, 07:53 PM   #19  
So how did it turn out?
It was actually not too bad out today, it was snowing when I came in from the shop at 2 this morning but it had to have been into the 50's this afternoon.

 
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05-09-10, 04:56 AM   #20  
Posted By: samuari So how did it turn out?
It was actually not too bad out today, it was snowing when I came in from the shop at 2 this morning but it had to have been into the 50's this afternoon.
Cruisin was a tad chilly, but out in the sun it wasnt bad. I ran 3/4gal gas w/ a can of seafoam. LOTS of smoke, and lots of crud on the plugs after I was done. I ran it out for about 2 miles and changed plugs. After changing to the QL78's, the backfire is about 90% gone. There is still a film of carbon on the top of the pistons, and I havent been able to inspect the rings for carbon caking but I think I will get a can of engine tuner and a set of head gaskets and pull the heads off to clean the pistons off. The engine runs a lot better - I checked idle timing which was off 4*, so I set it to 8* ATDC per the book. I can't do the Maximum spark advance/WOT timing check/adjustment as I dont have a "test wheel". When running it up to WOT from idle speed it still needs a little time to clean out.. seems to have a loaded cylinder that misses for a short time until it cleans out. All 4 plugs are still mostly white with just a slight hint of brownish/blackish residue after running for about 6 miles at 3/4 throttle. I have a feeling the low-speed mixture is a tad rich, and I need to get rid of the rest of the carbon to hopefully tame the smoking and keep an eye on the plug color. I still have a set of QL82's I might try until the water warms up a little more. During my tune-up yesterday, I could only get the engine up to about 100* since the water is only 60* or so... pretty cold.

Also - with the engine cover off, I could hear the VRO clicking.. thats supposed to do that, right?

edit: I was curious - whats the firing order on these engines, anyway? Not that it matters, but I was just curious.. Its not 1,3,4,2 like car engines, is it?

 
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05-10-10, 12:08 PM   #21  
Okay.. I'm getting a little frustrated. I went out yesterday, and it seemed to run decent for the first half of the day, but the afternoon it was back to misfiring and smoking like a chimney. The plugs (QL78) were still wet but the ceramic wasnt black like before. I changed to the QL82's and it seemed to have a smoother idle, but still had wet plugs. I leaned the idle mix a bit which resulted in drier plugs and a smoother idle but it still smokes pretty much every time you start it. The engine idles pretty good, and over 3000rpms it runs good, planes well but from off-idle to about 2500rpms is misfires. The carbs were rebuilt by the dealer when I bought the boat 3 seasons ago, but I havent had them off yet. I will take them off and clean them out and check float height. I will also run engine tuner through it before I take it out next. The oil consumption is getting expensive.. I have run about 30-35 gallons of gas so far this season and its inhaled a gallon of oil. Gas consumption varies, but is pretty consistent. I know the water temp is pretty chilly still, but the water coming from the indicator tube is luke-warm and I do not get any water coming out of the small exhaust port on the back of the engine. I'm coming to a few conclusions: I should replace the VRO pump, and vernatherms (thermostats) again. I should rebuild the carburetors and clean them thoroughly. It needs a compression test, waiting to get paid to buy tester kit. I'll look at the reeds too since the carbs will be off. I would think after replacing or rebuilding everything, that this would HAVE to fix this annoying and expensive problem. I also ran into one other problem.. When running above 2000rpm, volt gauge was reading 16 volts.. Do I need to replace something, or is this within acceptable range? Also - (sorry..) puzzling issue.. (I should just get rid of this engine it seems.) Sometimes when going WOT, it seems like the gearcase is skipping a tooth every now and then. It doesnt do it all the time, thats the puzzling part. This lower unit was replaced a year ago. (OBR Remanufactured) I have the shift rod screwed about half way in - shifts into forward and reverse and engages solid and fast, so I dont think the clutch dogs are messed up and after break-in the magnetic drain plugs didnt have many filings stuck to them.

Is this thing just doomed, or ....?
Sorry for the long post - I would have a shop fix it, but I just can't afford to pay shop rates. If its just a junk engine, I should just sell the whole thing and start over with something else... Any input would be appreciated.

edit: Rented a compression tester. Cold engine readings: #1,2,3,4 = 130,135,130,137. Head gasket was replaced on port side (2 & 4).


Last edited by Legal v8; 05-10-10 at 02:32 PM.
 
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05-10-10, 07:36 PM   #22  
I pulled the thermostat housings off tonight. the rubber grommet (on both sides) have a small hole in each one. I will replace these which should cure the low engine temps. I still have the high oil consumption problem among other things.. I will put a vac. gauge on the fuel line before the VRO to check for high vacuum readings and leaks. All of the lines are new with crimped clamps - not regular hose clamps.

 
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05-10-10, 08:47 PM   #23  
Compression sounds good.
Oil consumption is a little high at about 35:1. Something to try if you have the time. Take the oil lines off the vro pump and make a loop so it just recirculates the oil and pre mix your fuel at 50:1. That might be a cheaper fix than to replace the pump.

I can't remember but can you see the thermostats open? If you can put them in some water with a thermometer in it to test them. I know if those motors run too cool it will cause loading up problems.

These things can get frustrating but you will get itBeer 4U2

 
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05-10-10, 09:11 PM   #24  
Posted By: samuari Compression sounds good.
Oil consumption is a little high at about 35:1. Something to try if you have the time. Take the oil lines off the vro pump and make a loop so it just recirculates the oil and pre mix your fuel at 50:1. That might be a cheaper fix than to replace the pump.

I can't remember but can you see the thermostats open? If you can put them in some water with a thermometer in it to test them. I know if those motors run too cool it will cause loading up problems.

These things can get frustrating but you will get itBeer 4U2
Well, I'm going to use a vac. pump/pressure pump and troubleshoot the VRO *after* I replace a few more clamps on fuel lines and verify the fuel isn't restricted in any way. If all of the fuel restrictions go away and the t-stats are working, I am going to look into getting a diaphragm kit for the VRO and try that before doing the whole pump. A guy from iboats.com swears I have a air leak/fuel restriction causing the pump to suck air and pump extra oil. My shopping list includes a vac pump, 3/8" hose "T", clear vinyl hose, 1 can of OMC engine tuner, and 2 t-stat grommets. I will start a double boiler tomorrow and test the stats to see if they are opening or not - I have a meat thermometer that should work. Do I need to put pressure on the little pin in the middle of the stat or will it just sink in if its opening? They are sierra units rated at 143*. I need to know if they still offer the VRO rebuild kits, and what the cost is. 61 Sports and Marine is down the road from me, but their markup on parts is asinine. They want $28 for (1) 12$ carb kit. Not to mention they told me if I rebuilt my VRO that it'd blow my engine up and to replace the whole pump. (I hate that place, but its right down the road.... sucks...)

 
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05-11-10, 03:32 AM   #25  
The pix of the plugs look like oil fouling from too much oil in the mix. That could cause the symptoms you're seeing, including the pre ignition and cool running.

 
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05-11-10, 06:35 PM   #26  
Those plugs have already been changed out (BZ7HS-10). I do not have current pictures of the plugs I have in it now (QL82YC's). I am going to work on the engine tomorrow, I'll take pics of the plugs and post them. I am waiting for 2 new thermostat diaphragms which should cure the cool running temps, and I am going to troubleshoot the fuel system (again). I was looking at the VRO troubleshooting flow chart and it refers to a gearcase pressure tester and a gearcase vacuum tester to test the functionality of the VRO pump. Where the heck can I get something like this without having to order it and wait a week to get it? It says to first put 15psi pressure to the pump, check for pump clicks, then put 15" vacuum and check the other side of the pump. I have a manual vacuum pump, and a vacuum/fuel pressure gauge for automotive stuff but no pressure gauge.

 
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05-12-10, 03:51 AM   #27  
Point is, though, that new plugs will foul in short order unless the problem is corrected.

 
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05-12-10, 01:41 PM   #28  
Posted By: Rick Johnston Point is, though, that new plugs will foul in short order unless the problem is corrected.
I am WELL aware of that.. This is the reason I'm asking so many questions so that I can get it figured out. I've already replaced almost all of the clamps, and ALL of the fuel lines AND the oil line. Another guy says I still have a fuel restriction, so I am going to test the fuel lines for restrictions and air bubbles. I also need to test the VRO pump to ensure it is working properly. To do this, I have a vacuum pump/gauge already, but I need the pressure gauge w/ air fitting to check the VRO pump as well. If I find no fuel restrictions between the tank and VRO, then I'd assume the VRO is bad but ASSUME is a bad word and I want to test it but I have no clue where to get the tools to test it.

edit: I talked to another Johnson/Evvy mechanic and he said the VRO is most likely to blame. I am gonna just bite the bullet and replace the VRO. All of my fuel lines are tight, and free flowing. (I can blow air through the whole line with ease. Checkballs in primer are working as they should as well.) Not to mention there is some oil residue on the outside of the pump housing where the no-oil sensor is.


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05-13-10, 04:27 AM   #29  
I hope you get it figured out. Sorry I couldn't be of more help. Please post the results.

 
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05-14-10, 03:52 PM   #30  
Posted By: Rick Johnston I hope you get it figured out. Sorry I couldn't be of more help. Please post the results.
No problem - I appreciate all of the input I've gotten. I went through all of the fuel lines; although I didnt do a vacuum test on them I am certain that all connections are tight and free-flowing. I will just replace the VRO pump as its probably due anyway. I am just waiting for Samurai to get back to me on a price quote on a new pump. I got a can of Johnson Engine Tuner that I'll run through on sunday and replace the pump next week. Once I get it all put back together, I'll post back with results..

Thanks again to all that helped. I learned a lot more about outboards in dealing with this snarly issue.. I look forward to having it running good and right once and for all.

-Tim

 
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05-16-10, 09:00 AM   #31  
New question while I wait for the new fuel pump to come in. I got a can of the Johnson engine tuner - The instructions call to remove the prop.. Why is this? I was going to spray this stuff in today and let it sit overnight and run the stuff out of it tomorrow afternoon. I'll take the prop off if this stuff will damage it in some way otherwise will it hurt to leave it on?

Just curious.

Thanks,
Tim

 
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05-16-10, 07:43 PM   #32  
Keep the prop on.

It works better if you worm the engine up, spray it into the carbs until it chokes out and restart to do it again. Let it set overnight, then run it hard on the water to get it nice and hot.

 
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05-17-10, 04:41 PM   #33  
Posted By: samuari Keep the prop on.

It works better if you worm the engine up, spray it into the carbs until it chokes out and restart to do it again. Let it set overnight, then run it hard on the water to get it nice and hot.
Ok.. sweet... I'll do that before the long camping weekend.

 
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05-26-10, 08:07 PM   #34  
Okay.. little update.. I haven't had the boat in the water yet.. no time, but I did get a barrel to put the engine in to run it. I replaced the Thermostat diaphragms, and VRO pump. I went through every fuel system fitting and removed them, cleaned them, and sealed them with some high-temp thread sealing compound. I replaced the clamps on my fuel primer bulb with cinch clamps (the ones that came on it were junk), and did the same on the oil primer bulb. I replaced the spring clamps on the pulse fitting hose with cinch clamps as well. The engine now temps up nicely, doesnt misfire at all, and starts really well. I still have an insane amount of smoke, but I'm sure the crankcase is still full of oil from the bad pump. I pulled the air box off to see if there was any fuel leaking, and sure enough carb #3's float was too high - gas spewed out when you squashed the primer. I adjusted the float a little lower (dead level with carb body) and now doesnt spew gas. I ran out of daylight to test it this way, but when I take it out to go camping on the river I'll run it out and see how it does. I put a vacuum gauge on the fuel inlet between the bulb and vro pump before changing the VRO pump and got about 2-3" vacuum. With the new pump installed, I get about 1" vacuum with the engine idling. I'm amazed (even with the flooding carb) how fast it revs w/ the fast idle arm - its never idled up quickly like this... Hopefully after running it out this weekend, and running the engine tuner through it that the smoke will simmer down and it will run like a top.

Should you replace the impeller every year or can you go 2 seasons on the same impeller? I replaced the whole water pump assembly last year and havent changed the impeller yet this year.

 
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05-26-10, 09:03 PM   #35  
Sounds like you got it, good job.

The impeller should be fine every 2 years unless you are in real dirty water to wear on the blades.

 
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05-27-10, 10:04 AM   #36  
Posted By: samuari Sounds like you got it, good job.

The impeller should be fine every 2 years unless you are in real dirty water to wear on the blades.
Well, I figured if I sealed up every possible connection, there can't be any air bubbles or leaks whatsoever - which I dont believe there was beforehand, but I replaced them and went overboard (not literally) just to make sure. I didnt do the no-oil alarm check, but I know the low-oil alarm works and judging by the amount of smoke/oil in the water, Its gotta be working. I'll find out tomorrow. I still have to replace the rectifier/regulator module, but I can load the system enough to keep the volts down a little and can make due for now..

Thanks for the link to that pump - it saved me a ton of money! I really appreciate it.

I'll post back after the weekend with findings of running it in the water - if all goes well, I shouldn't have to bug you guys too much for awhile

-Tim

 
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06-08-10, 03:09 PM   #37  
95% improvement on almost everything I had issues with... Except this odd miss.. I don't think its a miss as its very sporadic and not predictable and only happens at WOT. When it does this "thing", the boat jerks once (like hitting a small log) and keeps going as if it never happened. I changed the gear lube (only had about 5-6hrs on it since I changed the lube after break-in of the new gearcase) The magnetic plugs had some shavings on them, well more like dust soaked with oil. I used Amsoil synthetic marine gear lube when I refilled.

After the new fuel pump, the engine starts cold a heck of a lot easier, idles better, doesnt smoke to oblivion and doesnt missfire/backfire nearly as much. (still getting a little bit but its pretty minor now.) Johnson Engine Tuner cleaned it out a little better, still have carbon on the pistons though.. (light) Here's my plugs as of the other day.

I've never had dry brown plugs in this engine. (I'm wiser now...) This engine has always had black oily plugs since I've owned it.. Everyone told me "Its getting plenty of oil, so you know its lubed good - don't mess with it".. They're full of it. This thing runs awesome now.. I just wish it went faster.. By having the engine run better, its about 3mph slower than it was in near-identical circumstances.

 
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