Motor craps out.

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  #1  
Old 06-24-10, 10:18 PM
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Motor craps out.

I just bought a 87 Reinell 185 with a gm 4.3 V6. The boat will idle fine, but once you get into the throttle, it will run for a minute or so and then just start dragging down until it just stops. I was hoping the fuel pump, replaced it, nada, carb float is not stuck, could it be a spark issue? It has a coil and a mechanical advance dist. The volt gauge says it's pumpin 14 volts, so I would assume its got power. I have replaced the fuel/water separator filter and the brass filter in the carb inlet, so I am thinkin it has to be spark? Could it be bad gas? Any help would be greatly appreciated!!
 
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  #2  
Old 06-25-10, 03:31 AM
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Welcome to the forums.

Could be bad gas if it's been in there for a couple of seasons without stabilizer. That also points to carb cleaning.

Two things I'd check:
Pull the distributor cap and check the points. Too much lube on the shaft spun some grease onto the points and caused the exact same problem on my '87 4 banger.

Or ... Carb's jets could be clogged up. If you don't know when the last time it was serviced it's time to pull it, disassemble, soak it in cleaner for a day or two, then rebuild with the kit.
 
  #3  
Old 06-25-10, 05:39 PM
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I don't know how long the gas had been in there, I know that I hadnt put anything in the gas tank (stabilizer). I will empty it and I also wondered about the cap and points.. Thank you for the ideas. Looks like saturday is gone. haha...
 
  #4  
Old 06-25-10, 09:02 PM
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I had a odd problem with a 3.0 4 cly in a 2009 glastron this week. The boat had water in the fuel so I drained it all out and tested it in our test tank and it ran fine. The cust took it out and said it acted the same way once wormed up so I figured it still had water in it so I pulled the tank to be sure it was clean and took it to the lake myself. sure enough it still acted up after about 15 min running it hard, it would act like it was dropping a cyl but had good fuel pressure and spark to the plugs. It turned out to be a bad spark plug.
 
  #5  
Old 06-25-10, 09:34 PM
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This one will run under throttle for only a min or two, but it just starts losing rpm, it doesn't chug or choke like if it were running out of gas, but just drags down and stops, let it sit for 10 secs and then it restarts and then the process starts over.. very odd.
 
  #6  
Old 06-25-10, 09:36 PM
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Is your fuel tank vented?
 
  #7  
Old 06-25-10, 09:42 PM
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You know, it is, but I hadn't pulled the hose to see if its blocked.. Ill have to check that.. Thanks for the idea.
 
  #8  
Old 06-26-10, 01:55 PM
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So I emptied the fuel tank, put new gas in it, the carb is shooting fuel in and it is still doing the same thing, also one thing I noticed is that the temp is rising up pretty quick, I pulled the theromstat housing and there wasnt a thermostat in there, should there be? Also the inlet hose from the outdrive is pretty dry, I have a set of those "earmuffs" for putting water into the outdrive and it seems that they are not pushing any water into the inlet hose, its just leakin water out past the suction cup deals. wouldn't hose pressure be enough to push water through that outdrive up to the motor at least?
Any help would be greatly appreciated.. Thanks.
 
  #9  
Old 06-26-10, 03:58 PM
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Sounds like you need to change the impeller, it should be changed every 2-3 years. The muffs shouldn't need to push any water after priming the pump.
 
  #10  
Old 06-26-10, 07:28 PM
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Water problem solved. I went to the boat shop, luckily they had the new impeller I needed, the other one was lookin beat. It's a water pumper now. . but it still drags down on rpm. I pulled the all old gas out and pulled the carb, gonna give it a rebuild and see what happens. Thanks for all your help. I will let you know the (hopefully) good news tomorrow.
 
  #11  
Old 06-27-10, 04:48 PM
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STUMPED! We cleaned the tank, rebuilt the carb, put new gas in it, nada, same old story, under throttle it drags down and dies. tank is vented, pulled gas out of a can to bypass the anti siphon valve, same story,
Now what, spark?? charging at 14volt, the coil has 9-10 going to it, cap and rotor look good, couldn't tell you how to set points and dwell (could use help with that) I had changed modules in other HEI dists' but I don't know what this one has or how to service it. This boat is killing me!!!
 
  #12  
Old 06-28-10, 08:12 PM
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I don't know the timing or points specs.
Have you changed spark plugs yet?
 
  #13  
Old 06-29-10, 04:24 AM
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Charging at 14 & coil at 9 is normal.

If this is a Mercruiser there should be a red sticker on one of the valve covers. It lists the plug gap, timing, etc.

Loosen the distributor so you can turn it while it's running. Maybe the timing isn't advancing? It still doesn't explain why it happens after a minute.

If the Merc engine has Thunderbolt V ignition (doubtful, but worth a shot), check the purple wire for a short to ground with the ignition off. This wire prevents the advance from working.
 
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