YM240 -starting problem/ blow-by

[tractor1971]

I would appreciate any advice!!

I have a very, very hard-to-start tractor, despite the thermo start. Will start very easily after it is warm, and runs smoothly, telling me the injectors are reasonable. No smoking is present, with only white smoke for a short period after start-up. Very little oil is used. A more knowledgeable guy told me the blow-by through the breather is excessive, and the rings are likely worn. Does this make sense with the little oil the tractor is using?

I am to the point where I want to rebuild the motor, just to see...

 

[Inspector507]

Are you sure the thermostart system is working? What temps are giving you the most touble?

 

[Normmm]

Try removing the air filter. If this makes it eaiser then replace the filter. Also check that the oil is not diluted. If it is change it.

 

[normde2001]

I would check all the easy stuff before tearing into the engine. Replace the fuel and air filters and bleed the fuel lines. change the oil with the correct oil, 15w-40 heavy duty, diesel rated. Remove the muffler and start it up to make sure muffler is not plugged. Use fresh fuel with an injector cleaner additive. Use the compression release to build oil-pressure and rpm's before releasing it to start.

 

[kenmac]

Diesels fire by way of high compression . a service manual would tell you how much compression is required to fire the fuel . If your compression is low it will be hard to start.When the engine gets hot it starts better because the fuel is being heated.

 

[tractor1971]

Thanks for the hints. Fresh diesel, used injector cleaner,have clean fuel filter. The thermostart work, checked with my own eyes after removing the air cleaner. Despite removing the air cleaner, same problem with starting. Will be almost impossible to start even in 15-20 Celsius, despite using my decompression to build up oil pressure. Oil was replace last season.

I have not removed the muffler, will try that this weekend.

How do I check the compression? I do have a service manual with the compression info.

Suggestions still more than welcome, thanx!

 

[Jagmandave]

On overhead valve engines, tight valves will also cause hard starting, and the clearances are easy to check, just pop the cover and get your feeler gauge out...........

Don't be tempted to use ether to help get it going tho.........

And yes, a worn compression ring will allow blow-by without using excessive amounts of oil

 

[greatrandini]

Does it turn over with significant speed when the engine is cold? My unit needs to be heated to start when temps are say 25 degrees f. The starter is just too week to spin the engine fast enough when it gets real cold. (even using the release) A block heater would be your best bet. Using lighter oil in winter helps it turn over faster. I run 30 wt. in summer and 15w40 in winter. u may want to run 10w30 in winter up there. I put a tarp over my tractor hood and place an oilfilled elec heater under the tractor for about 45 minutes and the rascal fires right up. I always keep it in the shed.

 

[tractor1971]

Turning speed is good, hot or cold. The valve clearance will be checked this weekend, as well as muffler.

 

[greatrandini]

I am guessing your unit has low compression! Check your compression and if it is low find out why!

 

[tractor1971]

My muffler seem to open, I am planning to open the motor. Any suggestions on what I will need ? I am handy with some knowledge on gas engines, and I have manual. Any suggestions on parts needed, taking into consideration that the only available parts must come from the US, and that this my only means of mowing my lawn is. I need to be prepared for the most likely scenario.

Parts will take a few days, and I will only be able to fiddle some evenings. Here is my list of parts I am planning to get.
1. Tappet cover gasket
2. Head gasket
3. Rod bearings
3. rings
4. ? crankshaft bearings
5. Manifold gasket
6. ?valve stem seals

Tractor has either 850 (likely) or 1850 hours (less likely), i hope the rest of mechanics is good.


Thanks again for the input.

 

[Egon]

Suggest you locate all the parts and find out delivery time. Wait til it's open and you can see what you have before you order the parts. [ EG. rings will not help a scored cylinder ]

Egon /forums/images/graemlins/grin.gif

 

[YanmarLover]

I'm curious as to where you're at with this beast currently, my 155 is doing the same thing as you described. I even had the cylinder head Professionally Rebuilt and triple checked my valve clearances, still acts up when under 70 degrees outside, will start willingly, once it's warm. However, it sounds like it's starting on one cylinder only. Once it hits 1500 RPM's, the second cylinder kicks in and it runs great. No smoke out exhaust, yet allot of smoky air out of breather tube. I suspect it needs a lower end rebuild. I live near Sacramento, Ca. I guess that if I take the engine out and bring the shortblock to a machine shop and give them Hoye's phone number and my credit card number, the machine shop would do the rest ? /forums/images/graemlins/confused.gif

 

[YanmarLover]

I'm curious as to where you're at with this beast currently, my 155 is doing the same thing as you described. I even had the cylinder head Professionally Rebuilt and triple checked my valve clearances, still acts up when under 70 degrees outside, will start willingly, once it's warm. However, it sounds like it's starting on one cylinder only. Once it hits 1500 RPM's, the second cylinder kicks in and it runs great. No smoke out exhaust, yet allot of smoky air out of breather tube. I suspect it needs a lower end rebuild. I live near Sacramento, Ca. I guess that if I take the engine out and bring the shortblock to a machine shop and give them Hoye's phone number and my credit card number, the machine shop would do the rest ? /forums/images/graemlins/confused.gif

 

[tractor1971]

I am in the process of rebuilding, my rings were shot, some wear only on the top part of the sleeves, but is it expensive to rebuilt! I replace my steering shaft due to water getting into the steering box, and I am at C$1200....