B-60 dies when warm

[Actonhorse 26]

Alright guys, I'm counting on you here. I recently did some trading locally with another wheel horse enthusiast and ended up with a really nice all original B-60. It has the original K161 recoil start kohler power plant. I didn't know what to expect out of the 7hp but it has really impressed me. I did the usual, new fuel lines, cleaned out the tank, new condenser, cleaned and rebuilt the carb and installed and gapped a new set of points. When I first got it, it had to run with the choke half closed or it stalled out. After the TLC, it starts on the first pull with no throttle and half choke. I can take the choke off almost immediately and it runs perfect.

Here's the problem... after cutting for about 40 minutes, it suddenly dies out like there is either a weak or no spark or it is not getting fuel. It will idle but that is about it. If I shut it off and let it cool, it starts right up and runs fine for another 1/2 hour. Then it does it again. It doesn't seem overly warm when it quits, it just seems to want a break...

Any advice would be very helpfull.

[VinsRJ 721]

Sounds like a bad condensor to me. When was the last full tune up completed? I mean like everything.... plug, points codensor, coil....

[Actonhorse 26]

I just did that, the condensor might have 2 hours on it. I also did a new set of points and plug. I have had them run bad if the points gap is off or the plug gap for that matter but this one runs perfect for 40 minutes under load and then quits.

[KATO 115]

Could be due to insufficient valve clearance (valve recession). And/or possibily weak springs.

KEN

[Sparky-(Admin) 21,254]

I had thought maybe the coil was quiting when it got hot, and then working again once it cooled off but it sounds like the motor never actually dies but only runs at an idle right?

Just a wild shot but try loosening the gas cap and see what happens. Could be vaporlock.

Mike...........

[rmaynard 15,383]

To elaborate on what Mike said, a clogged or blocked vent in the gas cap will provide the symptoms that you are having.The problem occurs when no air can get into the tank to displace the gas that is leaving This causes a vacuum to build up in the tank, hold the gas from flowing out.

[Actonhorse 26]

I had thought maybe the coil was quiting when it got hot, and then working again once it cooled off but it sounds like the motor never actually dies but only runs at an idle right?

Just a wild shot but try loosening the gas cap and see what happens. Could be vaporlock.

Mike...........

yeah, when it starts to die, if set the throttle to idle, it will keep running but has not power, if I go to engage the pto or try to drive it, it dies out.

To elaborate on what Mike said, a clogged or blocked vent in the gas cap will provide the symptoms that you are having.The problem occurs when no air can get into the tank to displace the gas that is leaving This causes a vacuum to build up in the tank, hold the gas from flowing out.

Tried that as well Bob, ran it for a while with the cap off once it was good again and it still died!.. the fuel filter is new as well and full of fuel.

One more questions, is it possible that if the plug or condensor is weak that they would be fine when cold but could get weak when they get hot?

[buckrancher 2,679]

where is the fuel line ran is down under the motor and up to the fuel pump or thru the engine between the alum. bearing plate and block?

Brian

[Actonhorse 26]

Through the engine..... I have no idea where you are going Brian but I am curious.....

[buckrancher 2,679]

your problem is vapor-lock the space between the alum. bearing plate and block is a dead air space run a new fuel line down under the blower housing and up to the fuel pump be mindfull of the muffler stay tight to the blower housing

the space between the block and bearing plate does not get any cooling air flow your boiling the gas in the line and vapor-locking the pump

Brian

[Actonhorse 26]

Yup, now I am glad I asked. That was definately not on my list of things to check! I will re route the line tomorrow and I should have to cut the grass on Saturday so that will give me a good chance to see if it is fixed. I will post an update as soon as I know.

Thanks guys.

[Anglo Traction 761]

I'm with Mike(sparky) on this problem. If it stops running and won't start until cool, It's a 'Coin Flip' on the Gas supply or the Coil, but I lean towards the Coil failing. If you have a spare Coil, or able to 'swap in' a known good one, it will confirm what the problem is likely to be, without tearing too much apart and no initial outlay.

[Actonhorse 26]

Yeah, I'm gonna try the fuel line reroute first as this is a recoil start and I would have to remove the flywheel to get at the coil and I believe from the research I have done that the coil is no longer available.....

[TT-(Moderator) 1,131]

Buy (or borrow) an inline spark tester. Check for spark when the engine acts up and I bet you'll see it weaken considerably.

The coil is still available - expensive, but definitely available.

[Coadster32 793]

_{Just a little reminder that new doesn't always mean good. I've replace old parts with new ones that were bad, and drove myself nuts. Pretty interesting Brians point though.}

[can whlvr 993]

any news yet dean?

[Actonhorse 26]

Not really, I was really busy on the weekend and was kind of under the weather yesterday, My son used it to cut the grass saturday but only ran it for about 1/2 an hour and it ran fine. I am gonna change the fuel line tonight and see what happens when we cut (again!) tomorrow. I did find a coil so I picked it up and that way, if it is the problem, I am ready!

[Actonhorse 26]

Well, looks like Brian was right. I figured I would go with the simple "fix" first and moved the fuel line, cut the grass (heavy) last night for about 45 minutes without even so much as a misfire! Im gonna assume it's good for now and time will tell.

By the way, here are a few pics for ya.

[can whlvr 993]

good lookin b there dean,gonna restore her or use her as a worker

[Actonhorse 26]

Thanks Don, I kinda like this one the way it is. I have a B-80 (my first restore) and I have all of the bits and pieces for a B-100 that is down to the frame right now and just starting to restore. That one is gonna take me some time as I want to do it right. When I did the B-80 I was in a bit of a rush as I needed it to mow with but now that I have a few choices I can afford to take the time....

[stevasaurus 22,632]

That Buckrancher is not just another pretty face. :) The knowledge on this site is amazing. I knew about the coil thingy, but when you said that you could keep it running, it was not that.