6lpa-stp not getting full power

[special k]

while not willing to let the professionals go "looking" @ $125 per hour i kept asking around about my issues. owner of my fuel dock told me of a boat with same engine and same symptoms. well a season later i finally catch up with said skipper and he was happy to share his experience with me. quite simple and requires no special tools or training.

on the injector pump, where the boost hose attaches, i simply removed the small diaphram cover. no gaskets or parts to come flying out. i found some water under this cover and the nipple that the boost hose connects to clogged with rust, apparently preventing the diaphram from lifting a needle valve providing more fuel. i cleaned top of exposed diaphram and reamed out metal nipple and re-assembled. four hex bolts and hose clamps were all that was involved.

result was that i regained the last 600 rpm that i was missing @ WOT and have my top end full load power back.
the trouble shooting procedures and proposed remedies from the pros would have cost thousands and there was still no guarantee they would have found the problem.

cleaning under this cover will now be part of my routine maintainance.

cheers!

[slimjim]

while not willing to let the professionals go "looking" _AT_ $125 per hour i kept asking around about my issues. owner of my fuel dock told me of a boat with same engine and same symptoms. well a season later i finally catch up with said skipper and he was happy to share his experience with me. quite simple and requires no special tools or training.

on the injector pump, where the boost hose attaches, i simply removed the small diaphram cover. no gaskets or parts to come flying out. i found some water under this cover and the nipple that the boost hose connects to clogged with rust, apparently preventing the diaphram from lifting a needle valve providing more fuel. i cleaned top of exposed diaphram and reamed out metal nipple and re-assembled. four hex bolts and hose clamps were all that was involved.

result was that i regained the last 600 rpm that i was missing _AT_ WOT and have my top end full load power back.
the trouble shooting procedures and proposed remedies from the pros would have cost thousands and there was still no guarantee they would have found the problem.

cleaning under this cover will now be part of my routine maintainance.

cheers!

thanks for this post. Can you take a picture of this and post it for us? I would love to see it. Jim

[special k]

i would if i were not tech-challenged

small round cover facing up on injector pump with small rubber hose attached. good look in the manual if available to you. hose called boost hose. my cover had 4 small hex bolts.

this was a perplexing problem with no answers even on boatdiesel fwiw

[halfmoon]

A simple suggestion. Are you putting the pedal to the metal? That is, does your throttle handle hit fiberglass? Mine did, and WOT was 3800. I loosened the Allen screw at the bottom of the handle, removed it and put it a spline back. Got 4000 rpm. Two mechanics had looked at the linkage and thought I was getting full range. The second mechanic gave me the suggestion to change the handle.

[special k]

throttle hitting the stops on the engine side, not a cable problem. that was my first thought when the problem first presented.

when the diesel "pros" couldn't find the problem with the usual filter changes and turbo wash they simply said it must be an issue with the boat, propping, dirty bottom, heavy load, yada yada. i am keenly aware of conditions on my boat and immediately dismissed their theory as a cop out.

as stated, my issue was on the boost side of injector pump, a simple fix that took forever to diagnose.

[DougSea]

i would if i were not tech-challenged

Are you tech-able to e-mail photos? Do you have a few?

If so, I can post them for you.

cdouglascampbell AT gmail.com

[slimjim]

i would if i were not tech-challenged

Are you tech-able to e-mail photos? Do you have a few?

If so, I can post them for you.

cdouglascampbell AT gmail.com

please email them to Doug so he can post what you are posting......

[special k]

i should be able to send pix via e-mail from my cell phone. i'll get a few shots of the parts this weekend.

cheers!

[DougSea]

And here you go:

image.jpg

[special k]

thanks to doug for help with the picture. as i explained prior, i removed the top hose clamp and hose from the metal nipple. then the four hex bolts and removed the cover. (no gasket involved) some water escaped as i removed the cover and top of diaphram was dirty with rusty gunk. also the end of the metal tube was plugged solid with rust. i reamed the tube, cleaned and dried all surfaces and re-assembled. that solved my power loss at WOT under load. the experts were at a loss to my problem and i just kept asking the boating/yanmar community till i found someone who had the same symptoms and resolved it. happened to be a boat nearby me on the mystic river.

seems to me that this seemingly simple cleaning of the boost hose area should not be a mystery to certified yanmar technicians.

i hope this can be helpful to the AOG community and all 6lpa owners.

we can't always trust the "experts"

cheers! cap'n mick 2002 28te

[slimjim]

thanks Mick.