1985 K17 Kohler loss of power on #1 Cylinder

[Vintage Mowers]

Okay.. First Off I have rebuilt a lot of small engines over the last 20 years and I have never had a problem like this. did a complete rebuild on a 1985 wheel horse with a K17 engine 17hp. the problem is it pops sometimes at idle through carb, doesn't have power under load compression is low on number 1 cylinder excess fuel build up. Now I can't see how it could have gotten out of time.. but wouldn't both cylinders act up if it was out of Time? the valves were done at the machine shop. I have heard that a baffle in the muffler can block 1 side I don't think that to be the problem. I guess I question the timing or a valve but I think that I maybe over thinking it, so Id like to pick someone's else head and see what they think, oh fly wheel key seemed fine too. have not run engine much because of problem. any thoughts??? also the number 2 cylinder warms up like normal and the number 1 stays cooler.

 

[ILENGINE]

I would start by finding the compression of both cylinders. If there is more than a 10 percent difference then I would follow that with a leak down test to find where the compression is being lost. You could have a exhaust restriction, but that wouldn't effect compression. Most likely a valve isn't sealing or maybe a broken ring, or faulty head gasket.

 

[reynoldston]

The very first thing I would do is a leak down test or compression test. Sound like a tight valve to me, have you checked the valve clearances. Isn't that the engine that has only one coil for both cylinders which fire at the same time ? So I don't see how it can be timing unless you have a bad coil. You did check the coil didn't you?

 

[Fish]

I agree, check the valve clearances first, even pull the head on the low compression side and look. Look closely at that intake valve.

 

[Vintage Mowers]

Thanks for the reply's. Yes there is big compression difference # 1 is very little compression. and Yes reynoldston that is the engine that has one coil and from what I can tell is okay. Also if it was a bad coil it shouldn't affect the compression I wouldn't think. From my test the head gasket seems okay. Yes I have pulled the head I think I question the exhaust side more than intake. The valves were done at the machine shop and set I didn't see in my manual where it gave me the valve clearances. I thought it said non adjustable. I will re check. It has the original valves in it they were re ground. New guides. I keep thinking Valve issue too. they say if the timing gets 1 tooth off it will cause the 1 valve not to close tight, but again if its on 1 cylinder I would think it has to be off on the other. I will check deeper into the valves on that cylinder as soon as I have time.

 

[reynoldston]

It sounds to me like whoever did your valves didn't adjust them proper. Intake .003 to .006 Exhaust .011 to .014 They are adjusted by grinding the end of the stems. If they grind the seats and valves they must also grind the stems. Their valve grinder has a attachment on it for this but I have done it in my shop with a power sander but be very careful if you do it because you can grind them too much without trying.

 

[Fish]

I agree, check the valve clearances first, even pull the head on the low compression side and look. Look closely at that intake valve.

Yeah, just check the valves first.

 

[Vintage Mowers]

It sounds to me like whoever did your valves didn't adjust them proper. Intake .003 to .006 Exhaust .011 to .014 They are adjusted by grinding the end of the stems. If they grind the seats and valves they must also grind the stems. Their valve grinder has a attachment on it for this but I have done it in my shop with a power sander but be very careful if you do it because you can grind them too much without trying.

Thanks again I will be checking into the valves This week. I did take a quick peak and it looks like there is no clearance in them. I have to wonder if the number 2 cylinder Valves are right too seeing this. I have never had the machine shop get them wrong before. as soon as I get time I will check them further .

 

[reynoldston]

Thanks again I will be checking into the valves This week. I did take a quick peak and it looks like there is no clearance in them. I have to wonder if the number 2 cylinder Valves are right too seeing this. I have never had the machine shop get them wrong before. as soon as I get time I will check them further .

We live a long ways apart and I don't know anything about the machine shop you used. I am just making a guess here. The reason I mention the coil is I had one in my shop this pass summer that ran like you described your ran and that had a bad coil but also that mower wouldn't run at all when it got warm. How did your mower run before you took it apart?

 

[Vintage Mowers]

We live a long ways apart and I don't know anything about the machine shop you used. I am just making a guess here. The reason I mention the coil is I had one in my shop this pass summer that ran like you described your ran and that had a bad coil but also that mower wouldn't run at all when it got warm. How did your mower run before you took it apart?

It ran and did have power but it was getting worse it was burning Oil as fast as you could put it in.. it didn't pop at an idle like now. It did start really hard when hot, but we assumed the condition of the engine was the cause of that. I have not ran it that long because of the problem now. I would assume if the coil was bad I would still have compression too. as far as machine shops there are very few around here anymore. I have only used this one 4 or 5 times but never had trouble with valves. the ones I used to use are gone. In fact there really are not any other ones around here now. there doesn't seem to be any clearance.. on either the intake or exhaust which would not be right.. I assume that I should get the clearance right first and see what happens. Not sure if we will try that ourselves or try the machine shop like I said my choices are very slim around here.