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endoftheroad 29-03-2011 07:54

Yanmar ysb8 injection pump question.
I recently removed my head and bought new injector as I had the "sooty exhaust, unburnt fuel, unable to load engine" problem that suggests faulty injector.

Well, my problem still exists, the exhaust elbow, hull bottom and prop are very clean.

Anyway, I have read that the injection pump will show similiar symptoms as the fuel injector.

So, I know am turning my attentions to the injection pump.

I do have some slight fuel seepage at governor arm at the injection pump.
My manual doesn't show a breakdown of that.

Can I first try to remove that arm and look for a gasket/seal instead of removing the pump?

If so, do I have to worry about timing?


nico105 29-03-2011 08:51

Re: Yanmar ysb8 injection pump question.
check for any air leak on the fuel sys before the I.P., the high pressure tubs that connect the fuel filter to the I.P. and/or the hose frm the lift pump to filter.
I had a bit of stripping on the banjo bolt on the fuel filter to the I.P.-small amount of air, causing white smoke, fuel sheen on water, lack of rmps.
Good luck, David

endoftheroad 29-03-2011 09:28

Re: Yanmar ysb8 injection pump question.
I have no air leaks.

I do have fuel seepage at top of injection pump at governor arm.
I may be loosing pressure to fuel injector causing improper atomization?

nico105 30-03-2011 03:46

Re: Yanmar ysb8 injection pump question.
Just to get it strait in my mind. Gov arm, internal engine prt that the fuel rack meets, sits in the v at the top of the gov arm, or the external regulator lever, or at where the high pressure tubs connect to the I.P. for each injector?
Maybe someone with abit more of a clue than me will chime in.
I am hopeful you will find the source of this issue for your Yanmar.

capngeo 30-03-2011 03:55

Re: Yanmar ysb8 injection pump question.
How much fuel are you leaking? If it is just a slight "weep" I would doubt it would affect pressure (and atomization). Now if it is more of a "drip" then you are probably on track! I'd pull the injector and see what kind of pattern it sprays... You want a "tulip" pattern.

I'll be out of town for two weeks, but if you're still having issues then, I'd be happy to stop by and take a look.

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