Oil & Fuel John Deere - ONE exhaust glows orange on full throttle

[tcartwri]

The compression test will not mean anything on a running motor. You need to remove the coil wire, and crank the motor over three to four compression strokes, with the throttle wide open.

 

[SPYDERLK]

OK, I found a picture of your engine ... is it a V twin :confused2: It looks like there is a black cover above the spark plug I can see. Removal of that cover would get you to the rocker arms controlling the valves for that cylinder. If you know where the timing marks to gauge crank position are thats great. If not it is rather unimportant because you can set the valves by watching for place where both valves are closed at the same time. -- Rotate the engine slowly in the correct direction and watch the valves cycle. By placement of the valves you should be able to tell which is for intake and which for exhaust. The intake is a down stroke of the piston. The valve then closes and the piston goes up for compression and then down for power then up for exhaust -- repeat. So all you have to do is watch the intake close and then turn the engine about 45 degrees further. This will be somewhere in the compression or power part of the cycle and both valves will/should be closed. You should be able to feel clearnce in the rocker arms. We are concerned that one of your exhaust valves is out of adjustment and not closing fully. If you find this adjust the threaded tappet to give about 0.010" clearance. That is safe, but youll want to find out the real spec eventually. Be sure all valves have clearance. ... ... However, before you go to this unfamiliar mechanical work, perhaps you should do the compression check 1st. It is done thru the spark plug hole. You may have a friend who has a gauge, or you can buy an inexpensive one at auto parts. Connect it to the subject spark plug hole, disable spark and crank the engine thru several revolutions. Compression should be 120+PSI on both cyls. If they are low check those valve clearances next.
larry

Yes the left side was (is) the glowing side. When I give more throttle to start up, it cranks for 4-5 seconds and eventually catches. When I do this the compression hoovers at 150 for the crank but as soon as it starts, the compression goes to 95-100 on the right side.

Same on the left now ( with throttle up). On both sides the compression doesn't get over 100 while running....it will get to 150 on crank but goes back down to 100 after it starts.

You dont do compression checks while running! Please describe what you are doing when you are checking compression. Some detail is needed. As it is theres no way to interpret what is happening. Guessing w/o real info doesnt count.
larry

 

[glassmanmike]

As I mentioned before, I am BRAND new to this...so bare with me as I make complete rookie mistakes. Obviously (to me now) what I was doing was wrong...does the following make sense:

- Remove the LEFT spark plug and insert the compression gauge in the left plug
- take the RIGHT spark plug cap off (so it doesn't start)
-open throttle to full
-turn the key to crank for several times
-read the compression gauge
-repeat on other side

Did I miss anything?

 

[tcartwri]

As I mentioned before, I am BRAND new to this...so bare with me as I make complete rookie mistakes. Obviously (to me now) what I was doing was wrong...does the following make sense:

- Remove the LEFT spark plug and insert the compression gauge in the left plug
- take the RIGHT spark plug cap off (so it doesn't start)
-open throttle to full
-turn the key to crank for several times
-read the compression gauge
-repeat on other side

Did I miss anything?

Just take both plugs out so that the engine will spin freely. You can count the number of times the needle on the gauge jumps. Min of four counts. If one of the cyl is a little low, squirt a small amount of oil into the cyl, and try again.

Please make sure the tractor is neutral if you are standing beside it. The starter is more than strong enough to run you over if it is in gear. ( disregard this last part, I just looked up what machine we're talking about lol )

 

[KubotainNH]

I thought I misread the post when it was said the engine was started with the tester in. I'm curious to see what you find. BTW, if it started with the tester in each cylinder then you have spark on both cylinders. Are these things electronic ignition? To me it looks like you'll need to pull the head off the right side. Curious though, didn't you say they both glowed in the beginning?

 

[SPYDERLK]

As I mentioned before, I am BRAND new to this...so bare with me as I make complete rookie mistakes. Obviously (to me now) what I was doing was wrong...does the following make sense:

- Remove the LEFT spark plug and insert the compression gauge in the left plug
- take the RIGHT spark plug cap off (so it doesn't start)
-open throttle to full
-turn the key to crank for several times
-read the compression gauge
-repeat on other side

Did I miss anything?

Just take both plugs out so that the engine will spin freely. You can count the number of times the needle on the gauge jumps. Min of four counts. If one of the cyl is a little low, squirt a small amount of oil into the cyl, and try again.

Please make sure the tractor is neutral if you are standing beside it. The starter is more than strong enough to run you over if it is in gear. ( disregard this last part, I just looked up what machine we're talking about lol )

:thumbsup: Good. If the engine has bad rings a little oil will give temporay improvement. Glassmanmike, the trouble with running the engine on remaining cylinders when testing is that the speed is so high and therefore the compression stroke is so quick that any leakage has little time to do its thing. Running can thereby give a higher compression to a bad cyl and make it appear better than it is. A good cyl doesnt care what speed because it doesnt have a leak. It gives good numbers even at lowspeed. It will be hard to use the oil trick to wet the rings because your cyls are tipped and the oil will to just go to the bottom side. Probably better to just let the running engine oil it. ... Start the eng cold and just let it run a few seconds at medium idle. Stop it, then immediately remove the plugs and check both sides. Let it sit a few minutes and check both again. Lets see how those numbers compare.
larry

 

[glassmanmike]

Ok- I just ran the compression test according to the above latest instructions.
1st time: (after running engine for 45-60 seconds on med throttle)
Left side: compression gauge fluxed from 145-180
Right side: compression gauge fluxes from 140-170

2nd time: (after letting sit for 5 minutes)
Left side : 150-180
Right side 150-180

What does that tell us!?

 

[glassmanmike]

Additional notes: after running the compression test (properly) this evening I decided to look again at the carb. I noticed the seal (brittle paper at this point) at the bottom of the carb lower housing unit was sticking out and was not seated properly. In fact the seal was warped and had some dirt buildup. I removed it and will look to replace over the next day or so. But I wonder if that is contributing to the Lean burn....poor seal on the carb?

 

[glassmanmike]

I thought I misread the post when it was said the engine was started with the tester in. I'm curious to see what you find. BTW, if it started with the tester in each cylinder then you have spark on both cylinders. Are these things electronic ignition? To me it looks like you'll need to pull the head off the right side. Curious though, didn't you say they both glowed in the beginning?

Yes, when I first got the tractor home, before doing ANY work, both exhaust manifolds glowed orange at 3/4 - full throttle. Now only left glows...

 

[Redneck in training]

When you reinstall the carb do not over-tighten it. It will warp the flange. In fact take a steel ruler and check if it is warped. If it is warped then flatten it by grinding it on a flat steel plate with abrasive paste or fine sandpaper.