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2 craftsman mowers with problems


DavePearson's Avatar
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10-03-06, 05:48 PM   #1  
2 craftsman mowers with problems

I just got 2 mowers, a craftsman 917.388041 with a Tecumseh 4.5 hp motor and a 917.389382 with a 6 HP B&S. Both have engine issues, hopefully they are not too hard to get running correctly.

The B&S starts fine, after a few seconds, the throttle starts to "hunt" (move back and forth) which causes uneven speed, missing, and eventually stalling. It may work better (it did the one time I did it) with the air cleaner removed, but it does not solve the problem entirely (I will be replacing the air filter). My gut tells me it is just a fuel issue, I may have to clean the carb, fuel filter (if it has one), but I just want to make sure I am not missing anything.

The 4.5 HP machine is a different animal. It is hard to start unless I manually open the throttle (there is no cable, I assume it is supposed to be on a governor). I can get it started, but unless I keep adjusting the throttle, it dies. I found it odd that there is a screw on the carb body (looks like an adjustment screw) that seems only to limit the travel of the throttle (I will have to look at it again when I am home during daylight hours).

I would really appreciate any info on any small engine repair manuals that may guide me through troubleshooting as well (but I will welcome any ideas you may have).

Thanks again,

Dave

 
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10-03-06, 06:29 PM   #2  
You didn't post any engine numbers, only mower boby numbers so I'm not sure what style carbs you may have, but it sounds like you're on the right track with carb rebuilds on both. I'm sure the Tecumseh would use a float style, but not sure on the briggs. Found a lot of different styles with different common problems. Post some engine numbers & the pros will set you in the right direction Good luck, Roger.

 
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10-03-06, 07:13 PM   #3  
The Tecumseh has the following info (I could find no tecumseh number, but I did get the Sears number off the engine, 143.034504. The only way I found out it was Tecumseh was by doing the model number search on the Craftsman site.

The B&S also did not have a engine number (that I could find), but the Craftsman parts list shows it as 12H802-2675-E1, which does match a B&S manual.

Thanks,

 
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10-04-06, 03:12 AM   #4  
Both, and most four strokers (as yours are), are governed. The screw you referred to, on the Tecumseh, is the idle RPM screw, which is redundant since the engine is a fixed speed throttle and the throttle shaft never comes into contact under operating conditions. The "hunt", also known as surging, is a lean fuel condition and both of these carburetors are in need of reconditoning, so it sounds. The Briggs carb kit part number is 498260 and is all you will need to buy for this engine and the Tecumseh kit is part number 632760B, but for this engine you may also need a 632019, float and you will need a 37793, manifold gasket and a 26756, carburetor mounting gasket.

 
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10-04-06, 04:19 AM   #5  
The Tecumseh

Thanks for the reply, I kind of figured that, but it's good to hear I was on the right track.

I think I am going to have to get a manual for the Tecumseh just so I can see how everything is supposed to be hooked up. The throttle (which should be on a governor I believe) does not move unless it is manually moved. There is a single linkage on the throttle control that does not move (and it spring returns to the fully counter clockwise position every time).

I am probably going to concentrate on the B&S, but would like to get info on how the throttle is supposed to be controled as opposed to what it is doing.

Thanks again!!

 
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10-04-06, 06:18 AM   #6  
Azis
Here is a link to a service manual that will cover the tecumseh
http://www.cpdonline.com/692509.pdf
Briggs site has owners manuals and illustrated parts lists that may help.
http://www.briggsandstratton.com/display/router.asp?DocID=64103

 
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10-16-06, 04:30 AM   #7  
Still a problem

Ok, on the B&S (I have not done to Tecumseh yet), I am still having problems.

I pulled the carb, cleaned and overhauled it. It still dies.

Updated symptoms:

Pump the bulb, gas goes into the carb, will not start unless started fluid is sprayed into carb.

Runs for a few minutes, then starts to hunt and pop. Looking a little closer, it looks like the auto choke (I thought this was the throttle until I looked inside and saw the choke flap... pardon my ignorance, I am new to small engines) is opening and closing and eventually chokes it out.

I start it again, it may do the choked out thing one more time, after which it runs fine.

Any ideas?

 
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10-16-06, 04:57 AM   #8  
Really confused

I looked at the IPL again, it is the throttle (there is no choke on this model). I thought it was the choke because the popping sound reminded me of gas igniting in the exhaust. The other symptoms are the same.

 
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10-16-06, 07:27 AM   #9  
Azis
When you prime the bulb are you sure there is fuel going into the carb throat?
Did you install a new kit? Bowl gasket? I think there is also a gasket on the air breather where it mates to the carb with a gasket that seals the primer system, it may need replacing. It is reference # 163 on the IPL and should be included in the carb kit.

If it does eventually start and run ok, but you have to use starter fluid, I would think your primer/choke system is not doing its job. Since you said yours has a primer, gaskets involved should be checked and replaced as needed. The bulb actually pressurizes the fuel bowl forcing fuel up into the throat. If the gaskets are not sealing or even a hole in the bulb, it may not be getting the prime it needs.

 
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10-16-06, 07:43 AM   #10  
Gas and bulb

There is gas going into the throat when I press the primer (I can see it).

I replaced the gasket to the air cleaner, gasket on the jet on the bottom of the bowl, and the gasket (O-ring) at the intake.

Part 130 on the IPL is always open (I can verify this later), I thought this was the choke (it looks like one), but I guess it is part of the throttle, when it goes closed, it boggs down (like it is being flooded by choking too long) and then when it opens, it pops. It does this when it is at an intermediate temperature.

 
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10-16-06, 07:46 AM   #11  
Have you tried a new spark plug? Could be a spark plug that is misfiring.

 
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10-16-06, 08:35 AM   #12  
Plug

That was the first thing I replaced. I am going to tinker with a few things tonight (or soon) just so I have a better idea of what helps it start.

The popping on the exhaust just before it does (watching the throttle, part 130, closing and opening and doing what a choke does) reminds me of something I used to do with a motorcycle (this was most fun going through a tunnel), I would hit the kill switch in high gear, let gas go through the engine and into the exhaust. Hit the clutch, undo the kill, let go of the clutch to turn over the engine and ignite the gas in the exhaust (quite a bang, but bad for exhaust systems).

At intermediate temps, it is acting like it is getting too much gas (or not enough air caused by part 130... what looks like a choke), then when it re-opens, more air gets in and it ignites (or floods out).

 
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10-16-06, 03:54 PM   #13  
Fuel Problem?

Anyone sick of me yet?

After a little more toying (what I should have done the first time), here are updated symptoms.

It starts easy cold, but I have to prime it at least 5 times (or more). I do not see this as a problem.

When it runs and dies, it is like it is not getting fuel (could it be opening and closing the throttle to try to get more fuel? That would not explain the popping, but when it dies, I have to prime it again several pumps or use starting fluid. I have opened the gas cap to make sure the tank is venting properly, but things are unchanged.

I am thinking air in a line somewhere, could it be an intermittant problem with the spark (which could only explain the need to prime when it dies if it corrected itself when there was a small amount of cooling).

This really has me baffled.

 
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10-17-06, 12:52 AM   #14  
Still sounds to me like you have a carb problem. I think something is restricted.


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God bless!

 
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10-18-06, 06:13 PM   #15  
Just for Goofs & Giggles, pull you're flywheel & check the key. Doesen't sound like that, but they can do strange things??

 
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