# 240D starting problem



## Ed Wells (Dec 27, 2008)

I just finished replacing a blown head gasket in a 240D that had been sitting for 4 years. While in the motor I replaced rings, rod inserts, and valve seals. The cylinders had very little wear, but the no 1 cylinder had some pitting due to water sitting it for 4 years, I honed both cylinders and they looked like they would seal. I cleaned the valves and valve seats, but did not reseat. They appeared to be in good shape.

After bleeding the fuel lines several times, I have not gotten the tractor started. All I get is white smoke.

I checked the compression and got 200psi on #1 and 250psi on #2. This seems to be low even for a new rings that haven't seated.

Does anyone know if this adequate compression to start? Does anyone know what the compression should be on this tractor? I have researched the internet, but haven't found it yet. Thanks in advance for any information you may have.


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## Live Oak (Dec 22, 2003)

Welcome to Tractor Forum Ed! The compression number sound pretty low to me. I'll leave this to the Yanmar guy Mark777, I am confident he will get you on the right track and in good shape. Sounds to me like you are not getting enough compression to light off the fuel and hence the white smoke. What thickness head gasket did you use? I would be VERY hesitant to use either on a newly refreshed engine. If you have the air cleaner off, try using WD-40 instead IF you determine you must go this route. I take it you have already checked the battery and connections and all are strong in and in good shape? The other issue, that might cause this can be timing the injector pump. Have you verified the timing is correct?


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## mark777 (Jul 23, 2004)

Ed, 

I agree with TF Admin...way to low of compression. You need 400+ psi per cylinder just to get it to ignite the fuel.

Everything sounds OK but I would question what the ring gap is? If it's too wide then no top end build is going to help with the fuel'air rushing past the rings. Another possibility is taper in the cylinder liners. When you checked, did you drop a piston ring at the bottom and check the ring gap...and do the same at the top of the cylinder? Using a feeler gauge and checking the ring gap at both positions WILL tell you if, and how much taper there is.

The compression ratio on the 2TR20 engines (YM240'YM2000) is 20:1, and from memory the cylinder pressure should read 575-625 per compression stroke. When you did the test, did you remove and replace one injector at a time?

Good luck,

Mark


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## Ed Wells (Dec 27, 2008)

Wish I had checked the ring gap, but there was very little wear showing on the cylinders, so I assumed them to be okay. I have tried wd-40 with no luck. 

With your information and all that I have read on the internet forums, I now believe my problem is low compression. The starter is turning the motor over too easily for the compression to be at the proper level. From what I have read, the yanmar starters are notoriously undersized and most have to use the compression release to get the motor going.

Thanks for the quick response and for your help. I will do a more thorough job the next time in.


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