Jump to content
Sign in to follow this  
algrc120man

engine trouble

Recommended Posts

algrc120man

ok ive been working on kohlers for 15 years now have never had the trouble of the engine running well at idle and full throttle except that at full throttle it will only run for about 2 minuets then sounds like it looses compression and dies does not loose fire or fuel when this happens will idle all day i checked the valves crankcase vacum and also measured the acr lift distance on the ex valve it reads .033 which is with in spec kohler says up to .042 replaced fuel pump coil points condenser spark plug . so my question is does any one agree with me when i say that there may be a a problem wit the acr mechanism when engine is at full throttle for a short time that it activates and opens the ex valve and shuts down . the odd thing is that imediatly after shut down it will re start and do it all over again but prior to shut down it has good power will run the hydro and mower well. also cleaned and rebuilt carb. any insight would be awsome thanks :thumbs::thumbs: :thumbs:

Share this post


Link to post
Share on other sites
 
WH nut

Sounds like you may have a fuel supply problem. Try this get a can of carb, cleaner, or even WD40 and as it starts to die give it a shot of juice and see if it trys to stay running

Share this post


Link to post
Share on other sites
 
algrc120man

ill give it try thanks rick

Share this post


Link to post
Share on other sites
 
rmaynard

I can't see where the ACR would be at fault. If you are familiar with how the ACR works, centrifugal force moves the ACR holding piece away from center as the speed increases, allowing the "lobe extension" to drop out of use. It only has to overcome the force of a tiny spring. If the spring fails, then the ACR mechanism fails, but it fails safe. In other words, it fails so that the ACR does not work. Your engine would be harder to turn over when starting, but it would not effect the compression at higher speeds.

Share this post


Link to post
Share on other sites
 
Kelly

I have a 16hp Kohler that has gave me fits for a few years now, it idles great, some times powers up nice, but most times when i get it throttled up, to a steady speed it acts like the exh. valve is hanging open, even sounds like it is firing through the exh. it has a stack on it, bring it back down to a idle it runs great, throttle it back up half it runs good, full throttle same thing but not everytime, most times but not all. I've thought about the ACR, I've rebuilt the carb, fuel lines filter, pump, the carb is very touchy so i know it's clean dirty carbs don't take adjustments well, I pulled the head new gasket, cleaned the carbon still same problem, I need to pull the cam cover to see if anything is amiss.

Share this post


Link to post
Share on other sites
 
hm12460

I would suggest taking a good hard look at the lip on your exhaust valve and make sure it is within spec. Very easy to over look. I went through this problem several years ago on a John Deere 210 with the K-241 engine. A new exhaust valve cured it.

Share this post


Link to post
Share on other sites
 
can whlvr

i know this sounds simple but check that your fuel tank is vented,this will cause troubles like u have also

Share this post


Link to post
Share on other sites
 
WH nut

Kelly if yours has a stack on it, I would check the exhaust valve very close. If it has sat outside without a rain cap on it the vlave could be rust pitted from rain going down the stack. You may have to remove the valve to see it.

Share this post


Link to post
Share on other sites
 
Irv

I agree with Don, check that gas cap!

Share this post


Link to post
Share on other sites
 
rmaynard

A blocked vent hole in the gas cap would cause the engine to quit running until the vacuum is released from the tank. He says that there isn't a lack of fuel, and it idles fine after the problem occurs at higher RPM's. With a blocked vent, it wouldn't idle either, it would just die.

Share this post


Link to post
Share on other sites
 
Duff

How about a partially clogged hole in the vent cap? At full demand for fuel the vent might not be able to keep up, but at lower demand or after the engine shuts down the vent might "catch up" enough to take care of the negative pressure.

Just another thought.... :thumbs:

Duff :thumbs:

Share this post


Link to post
Share on other sites
 
WH nut

How about a partially clogged hole in the vent cap? At full demand for fuel the vent might not be able to keep up, but at lower demand or after the engine shuts down the vent might "catch up" enough to take care of the negative pressure.

Just another thought.... :thumbs:

Duff :thumbs:

Thats why a shot of Carb cleaner will help narrow it all down. If it stays running then you know its a fuel delivery problem :thumbs:

Share this post


Link to post
Share on other sites
 
rmaynard

How about a partially clogged hole in the vent cap?

Easiest way to see if it's a clogged or partially clogged vent is to loosen the cap. If the problem goes away, you've got a bad cap.

If the problem has become consistent, I would be more inclined to think it was a weak valve spring. At low RPM's a weak spring will not exhibit any problems, but at maximum RPM, the valve can float causing a lack of compression and loss of power.

Another note about ACR. The ACR mechanism only works under 600 RPM's. Idle speed should be around 1100 to 1200 RPM's. If the ACR were to be defective (not releasing at all), you would have the problem at idle as well as full speed.

Share this post


Link to post
Share on other sites
 
algrc120man

ok i gave it a shot of carb cleaner as it sstarted to die it did not help it was dark out when i done it sounded like it started loosing power and started to show fire coming out the muffler and then got lots of fire as it died sounded like something would when a valve hangs or a seat pops loose just loseses comp . this happens a mid range or full throttle. tried the following new fuel pump fresh gas new points condenser plug plug wire checked valves de carboned did vac test checked acr lift height it reads .031 within spec i am now suspecting a weak spring on the ex side valve no blocked gas cap thanks for input also cleaned and rebuilt carb. :thumbs::thumbs: :thumbs:

Share this post


Link to post
Share on other sites
 
WH nut

Pull the valve cover and check your clearances,

Share this post


Link to post
Share on other sites
 

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

×
×
  • Create New...