TROUBLE BLEEDING YANMAR 3YM30

Jun 20, 2010
3
Catalina 309 San Carlos, Sonora, MEX
I have a Catalina 309 with 1008 hours on an engine that has been well maintained. Repeated bleeding of the injectors has not allowed starting the engine. A mechanic has indicated that it is a simple problem (which he will not disclose). Does anyone else have knowledge of a simple explanation or fix for this problem? Fuel is clean, filters are good, lines have fuel to the injection pump, motor turns over at a good speed when trying to start.
 
Jun 21, 2004
2,532
Beneteau 343 Slidell, LA
Puzzling indeed.
Usually bleeding at primary & secondary filter by using the priming lever on the fuel pump on the 3YM30 is sufficient as it has an "auto bleed" feature. Last time I changed filters, that's all I had to do. For some unknown reason you may have to start all over again and the bleed the filters again, then bleed at each injector to get it going again. If that doesn't work, you may have to call the mechanic.
 
Jun 21, 2004
2,532
Beneteau 343 Slidell, LA
Was there a problem that prompted you to bleed the system or were you doing preventive maintenance, changing, filters and then had the starting problem?
 
Sep 29, 2008
162
Morgan Out Island 33 Pompano Beach
Sounds like your "mechanic" is trying to hold you up...not fair. Look at the racor filter. If the bowl is cracked it could be lettig in air. Otherwise track the fuel syastem for some other leak. Bob
 
Jun 6, 2006
6,990
currently boatless wishing Harrington Harbor North, MD
You have air in the fuel lines. Start at the filter and work toward the injectors. use the manual pump feature on the engine primary (low pressure) fuel pump.
 
May 20, 2016
3,014
Catalina 36 MK1 94 Everett, WA
You didn't accedently hit the decompression lever when bleeding did you?? ( you did say easy fix)

If you really think it fuel, submerge the tank return line in a clear container and see if you are blowing bubbles.
 
Dec 19, 2006
5,809
Hunter 36 Punta Gorda
I have 2007 H-36 and has a 3YM30 and did bring her in for service after 90 days and was told the YM are self bleeding and so when I did have a hose leak real bad it did restart right up and every time I change filters never need bleeding and so must be something else.
check and make sure your getting fuel to the small up front fuel filter.
Nick
 
Jun 8, 2004
2,841
Catalina 320 Dana Point
If your getting fuel out the bleed screw on the on engine filter, try checking the exhaust elbow as Weinie suggests. When was the last time you changed the exhaust elbow ? Yanmar recommends checking every 250 hrs. and replacing every 500. I have a different elbow on my 3GM30 that only makes it 300-400 hrs before clogging.
 
Dec 19, 2006
5,809
Hunter 36 Punta Gorda
If you think it could be the mixing elbo just easy and quickly unbolt the 4 bolts and just seperate it and than try quick start
and did this once and was the mixing elbo and started up quickly
 
Jun 8, 2004
2,841
Catalina 320 Dana Point
Also, if you remove air filter and it's sooty, tries to "backfire" or spit out the intake while cranking and it's damp with fuel around intake you are getting fuel and the elbow is PROBABLY clogged. Any chance your mechanic did something like that ?
 
Jun 21, 2004
2,532
Beneteau 343 Slidell, LA
Again, was it running prior to attempting to bleed the system? If so, it's probably not the elbow. Not saying that it doesn't need to be inspected / replaced, but if it was running prior to bleeding the fuel system there is something else happening here. Go back and attempt to bleed the entire system again and while you're at it, check for possible leaks.
BTW, the 3YM30 does not have decompression levers.