Fatman

Can't figure out why it won't run

24 posts in this topic

So I got this mower for off-road use. It was built up as a pulling tractor is the story and is supposed to be pushing 21 horse. It's a kohler 341 engine. Well it was cheap so I got it and figured I'd take a chance. I have gotten it to run for about 20 minutes without touching it but it ran real rough other than that it doesn't wanna run. I've changed the carb, check the fuel line all the to the carb and fuel flows good and fuel pump works good. I've set the spacing on my valves and points along with replaced spark plug. When I lay the spark plug on the engine it still gives a spark. I just don't understand why it doesn't want to run. I have also tried the gas cap off trick and nothing. My best bet is starting fluid but after that burns up it dies 

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Since you did the basic fuel and ignition checks, check the compression to see if you have a viable engine to work with. Report your findings.

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I just haven't seen a reason to because when I take the spark plug out and feel the blast of air come out of the hole when I crank it, it seems like a crazy amount 

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ID: 4   Posted (edited)

Welcome to Red Square !

If she runs on spray my guess is your issue lies in fuel delivery .

Let's see a pic or two of that carburetor...

 

 

 

Edited by Digger 66
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Welcome to Red Square. Fuel delivery is my 1st question too! Clog? Carb bowl? Carb itself?

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ID: 7   Posted (edited)

Maybe the in tank filter is plugged up?

Edited by scotty
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Yep, these guys know......If it runs on fuel sprayed into the carb then stops when you quit spraying,  you have a fuel delivery problem.     You said you changed the carb, with what, new, old rebuilt?

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3 hours ago, Ed Kennell said:

Yep, these guys know......If it runs on fuel sprayed into the carb then stops when you quit spraying,  you have a fuel delivery problem.     You said you changed the carb, with what, new, old rebuilt?

Yes carb is new. I have replaced the fuel filter, cleaned fuel lines out, taken gas tank off and check if it was clear, checked gas cap and it's cleared at the pin hole, I've made sure the gas flows steady after the filter and also checked that the fuel pump was pumping good and it squirts a stream. I tried to adjust a screw on carb today and it snapped on the new carb. Pretty mad about that but I'll get old screw out and replace with one off old carb 

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10 hours ago, Fatman said:

I just haven't seen a reason to because when I take the spark plug out and feel the blast of air come out of the hole when I crank it, it seems like a crazy amount 

If you are asking for help, I suggest you follow instructions given and report back as requested. There is a reason people ask you to perform certain test to diag your problem. if you don't follow a logical sequence of testing you will be all over the place and may never find your problem.

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5 hours ago, Fatman said:

Yes carb is new.            the fuel pump was pumping good and it squirts a stream.                                    I tried to adjust a screw on carb today and it snapped on the new carb.

New carb.

Fuel pump supplying a good stream to carb.

You broke a jet screw by overtighting.  The seat is likely damaged and will need to be replaced if possible.

To set the jets on the carb, you turn them in  gently till you feel them  touch the seat, then back them out the proper amount shown in the manual for your carb.

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ID: 14   Posted (edited)

 

 

23 hours ago, Fatman said:

set the spacing on my valves and points along

:WRS:     If it was running well I doubt the valves suddenly got out of adjustment,   :twocents-02cents:

You have compression, fuel and spark, now you need to have them in proper proportion at the appropriate time. The points gap also sets the ignition timing on these engines. Read over this attachment and reset the points to obtain proper timing and see what that does for you.

Kohler static_timing.pdf

 

 

 

 

 

 

 

 

 

 

 

Edited by 953 nut
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How is it working out for you?

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On 12/30/2016 at 5:12 PM, lynnmor said:

Since you did the basic fuel and ignition checks, check the compression to see if you have a viable engine to work with. Report your findings.

This comes up time and time again how do you check compression on a kohler with automatic compression release?

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1 hour ago, prondzy said:

This comes up time and time again how do you check compression on a kohler with automatic compression release?

Some have had good luck turning the engine backwards with the gauge in place.  Other than that, a leak down test may be needed.  Anyway, if the OP does the compression test in the conventional way, it might tell us something if he reports near zero.

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11 hours ago, lynnmor said:

Some have had good luck turning the engine backwards with the gauge in place.  Other than that, a leak down test may be needed.  Anyway, if the OP does the compression test in the conventional way, it might tell us something if he reports near zero.

No it wont the compression has been released.

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The compression is released when the piston is two thirds of the way up, so there will be a low reading.  Turning it backwards, the compression isn't released till the piston is approximately all the way up.

 

If possible, the exhaust valve can be adjusted with about .040" excess clearance so that no compression is released.

 

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Even with the compression release you will still have about 50 pound while cranking. If you have zero you know you need to do some exploratory.

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one trick if a guy has another horse is to hook up the ptos with a belt,i believe you figure 8 it to turn the (DEAD TRACTOR) over

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The lever on the fuel pump may not be moving and it is not moving the fuel so take the fuel pump off and pump it by hand to see if fuel comes out if it is not that may be your problem.The lever is in the block on the fuel pump.:USA:

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Just seeing this post.

 

Agree initially that it was/is a fuel delivery problem. I would have suggested bypassing the pump, and feed the carb directly from the tank. That would pinpoint/eliminate the fuel pump.

 

It's easy to get frustrated and do a bunch of stuff all at once, but it tends to lead into more problems more times than not. Patience is the best practice with a frustrating problem. Lots of knowedge on this board. If you're new at this sort of stuff, (Without alot of common knowledge), all you need to do it let us know up front. We are here to help.

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Beyond this, I would check in to camshaft timing and give the lobes a serious scrutinizing. There are people out in the world that these engines can be played with like a hotrod. your comment about the engine running rough and pulling almost 21 hp makes me question what may have been done. Has the head been reworked to increase the compression ratio?
I have heard of such, do this checking as a last resort.

I would question this BUT........

 

Ron

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