Try installing a priming bulb so you can pressurize your fuel lines/system and check for leaks after a while. That may be the most reliable way to locate a leak on the low pressure side of the fuel system. I would install it between the tank and the prefilter, good luck.
A mistery problem on my 2GM20F, any advice?
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Thanks, have been thinking about installing a bulb, leaning toward doing it, might be beneficial In the future as well.
Thanks!
Thanks!
First of all you have to correct that air leak. Stu, once again hits a good mark, the bleed screws on the Yanmar have a short useful life and it is likely that with all that bleeding yours could be ready for replacement. Once you have stopped the air leaks it would be time to evaluate anew whatever symptoms may be present.
Thanks. Bleed screw if fine. I use the larger one, that has a copper washer, and change the washer every time (have gone through many but they are cheap).
On an update, I had a few minutes to go to the boat and checked a few things. I opened the primary Racor 500 filter and the fuel was about an inch below the top of the element...hmmmm....can't remember now if I fill it up when changed the filter (bad, I know)...now two options, I didn't fill it up and never got to bleed all that air on the top of this filter (I guess the engine was sucking just a bit of air but not enough to kill the engine)...or their is an air leak between the tank an the filter and that is how the air got there. I bled it again, this time for several minutes until clearly no bubbles where showing....run it for 30 min in the mooring, since had to leave, and all ok. Will give it a try this weekend under load and see if anything has change. Will report back. Crossing my fingers
Thank again everyone
On an update, I had a few minutes to go to the boat and checked a few things. I opened the primary Racor 500 filter and the fuel was about an inch below the top of the element...hmmmm....can't remember now if I fill it up when changed the filter (bad, I know)...now two options, I didn't fill it up and never got to bleed all that air on the top of this filter (I guess the engine was sucking just a bit of air but not enough to kill the engine)...or their is an air leak between the tank an the filter and that is how the air got there. I bled it again, this time for several minutes until clearly no bubbles where showing....run it for 30 min in the mooring, since had to leave, and all ok. Will give it a try this weekend under load and see if anything has change. Will report back. Crossing my fingers
Thank again everyone
Jus a quick update to let you know hat it was air in the fuel, very interesting how this can have an effect on performance (low max RPM) but no issues starting and running the engine at low rpm.
I think the culprit was a half full racor 500 filter, either from an air leak or from not filling it up when changed the filter. I made sure all clamps in hoses were tie, and change o rings on racor filter, then bled the system until I was 100% sure no tiny bubbles were in it.
Hope this helps someone else with similar issues.
Thanks everyone for your comments!
Abe
I think the culprit was a half full racor 500 filter, either from an air leak or from not filling it up when changed the filter. I made sure all clamps in hoses were tie, and change o rings on racor filter, then bled the system until I was 100% sure no tiny bubbles were in it.
Hope this helps someone else with similar issues.
Thanks everyone for your comments!
Abe
I didn't see
I didn't see the air filter mentioned. The Yanmar filters are some kind of foam, and come apart with time. Starving for air will cause exactly the problem you describe. I changed mine air filter to a K&N, couple years ago. Just wash it from time to time.
I didn't see the air filter mentioned. The Yanmar filters are some kind of foam, and come apart with time. Starving for air will cause exactly the problem you describe. I changed mine air filter to a K&N, couple years ago. Just wash it from time to time.
Good point, though did change the air filter. So far so good with the engine, air appears to be the cause of what was happening. I have space to relocate the racor filter lower than the tank (juts an inch or so) so so gravity can fill it, I might be doing that to reduce the chances of this happening again.
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