Bogging down....

[Wakuu]

My engine is a Perkins 4.108 and my transmission is a Hurth hydraulic model (don't have exact number in front of me)

Engine runs great while in neutral throughout the throttle range. The moment I put it in gear, either forward or reverse, it bogs the engine down and if I did it from idle throttle, it will usually kill the engine. I can engage from a little higher than idle and it will produce minimal thrust while bogging down to an idle RPM level and putting out black smoke (I assume unburnt fuel from me trying to throttle it up)
Some things to note:
1) Shaft turns easily by hand.
2) Rubber coupler between transmission and driveshaft
3) Loosening shaft packing doesn't help.
4) In neutral, at idle, the shaft turns slowly on its own...always has.
I've run this by my "Perkins guy" and he has no idea. I have about 6 people coming to stay with me and go sailing for the 4th....HELP!!!

[a64pilot]

prop badly fouled?

[Wakuu]

I should have mentioned that my diver is on the bottom every 2-3 weeks and I have a clean bottom. I even hopped in and took a look just to make sure. Totally clean under there.

[Wakuu]

Ok...maybe I don't have a Hurth....did some image googling and didn't see mine anywhere....here is a picture of what I do have....

[sharpey]

I'd be thinking something's up with your transmission then...

You mention it's a hydraulic hurth.. Any idea on the specific model?

If you've had it serviced recently, the wrong fluid may have been put in... some need ATF, others need gear oil.

[Cap Erict3]

While it might be a transmission problem I would start cracking your injector lines one at a time while at high idle to see if you are firing on all cylinders.

[MARINE ENGINNER]

Originally Posted by Wakuu

Ok...maybe I don't have a Hurth....did some image googling and didn't see mine anywhere....here is a picture of what I do have....

there isn' any picture.can you upload it again


M.E

[StuM]

Originally Posted by MARINE ENGINNER

there isn' any picture.can you upload it again


M.E

I can see it by following the link in either the original post or your quoted reply

[Ex-Calif]

Originally Posted by Wakuu

I can engage from a little higher than idle and it will produce minimal thrust while bogging down to an idle RPM level and putting out black smoke (I assume unburnt fuel from me trying to throttle it up)

If the drive system runs free and clear as you state - packing gland gearbox, prop not fouled - it seems you have a low power problem.

You could get a thermal gauge - these are cheap and handy to have - and check the temps at each cylinder to make sure they are all hot and relatively equal. I low temp could indicate a fuel delivery problem - injector maybe.

If all are equal then I would do a compression test. Does it start easily? If it does it may not be compression.

Also check that inlet is clear and not restricted. Same with the exhaust system. Broken baffle or some other item could be restricting the exhaust system.

[Wakuu]

Ok figured it out. Two cylinders not firing due to fuel leaks on two lines. Will take out exhaust manifold and fix it.


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