Engine Compression

   / Engine Compression #1  


Bronze Member
Oct 4, 2016
Hemet, CA
Yanmar 240D, 8N Ford
Having trouble starting a Yanmar 240D. Used it and parked it. Now getting lots of white smoke but doesn't even make a pop even with a block heater making it warm. Last try I decided to adjust the valves and I was able to put a 8" wrench on one of the front pulley nuts and turn the crank fairly easily to adjust the valves. How hard should it be to turn the engine over? And is the TDC mark on the front pulley the proper spot to set the valves? There is a clear difference in starter effort when I release the decompression lever so I thought I had decent compression but perhaps not. Been raining a lot here and possibly water contamination so will drain the fuel tomorrow and replace. How long will it need to crank to get the old fuel out of the lines and get to the clean fuel? I'll also redo the valve settings again but have my doubts that that is the problem.
   / Engine Compression #2  
White smoke, and lots of it, can be a few things;
  • bad injector
  • water in the fuel /engine (e.g. rain through the intake)
  • coolant leaking into the pistons
(As a diesel,owner, I think that it is worth reading and knowing the other colors As well.)

Given that you notice a difference with the decompression lever, I would lean toward water / bad injector. I would check the whole fuel system, draining if necessary, and then check the injector patterns / function. As to how much diesel to drain, drain each segment of the fuel system into something clear and look for water. I start at the tank and move toward the injectors, pushing "known" clean diesel step by step through the system.

Good luck,

   / Engine Compression #3  
Replace the Fuel Filter and Bleed the System. Drain the tank. Not much to it. Charge the battery so your getting as much power to the starter as possible. Napa.#3262 I'll be replacing mine again at the end of this Season. They get dirty mine was real bad the first time I replaced it. I don't run oFF Rd, Diesel since you can't see how clean the bowl and filter is the from the Red Dye. ;) Does your Muffler have a lid on it preventing water getting into the Exhaust? It could have water in it from the all rain you stated having?


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   / Engine Compression
  • Thread Starter
Oddly enough, before I tried starting it, I noticed that the bolt-on muffler cap had been twisted, probably by a tree branch. Before I get too crazy, I'll drain the fuel, new fuel and air filter, and bleed the whole line. If I just take the muffler off will it have any effect on starting it? Thanks, for the suggestions!