4jh4-TE Low Revs

[svBeBe]

I have the same engine and have experienced the same low rev problem.

Every time it has been the slightest amount of growth or fouling on the AutoProp. The AutoProp pitch will change with fouling causes over-pitch and low revs.

I only bring this up because it is not clear that you found the problem.

Bill

[hpeer]

There is no lift pump or fuel feed pump. The manual I have for this family of engines shows both variants, the one has the side mounted feed pump, while the TE/HTE does not. The engine has never had a feed or lift pump, and my tank is integral to the keel so that from the lowest point I have over five feet, maybe six feet of lift.

In e meantime I have installed a day thank that I am filling with a Whale shower sump pump that is also sold as a,fuel transfer pump. The day tank is about the same level as the injector pump. But still, on this engine, no feed pump is required. I left off a fuel return line last night when i was first running the engine. What a mess, that pump really pushes through the fuel.

I don't know what fixed the low rev problem. It is possible there was air getting into the system but I more suspect that there was some dirt in the injection pump. Apparently the pump shop said they had to clean out crap but the pump was ok otherwise.

Thinking back to the night this occurred I think I may have had a Racor issue. When I first lost power I changed the Racor, still did not have full power and then changed the Yanmar filter, which I found to be really dirty with some big stuff, stuff that should not have gotten through the Racor. Just a thought.


As to the procedure.

First I lined up the timing marks, then I made corresponding marks in the crank shaft on the front of the engine so I could more easily see where I was in the stroke cycle.

Second I pulled all the injectors and put them on the hard lines facing up so I could see when I was getting a squirt.

A finger in the injector hole confirmed compression stroke so as to not get 180 out.

Pump up fuel line using pump on top of filter to get air out of lines. Turn crankshaft with a socket set to exercise pump and observe where the squirt is in relationship to the cycle and TDC. Use a compas to measure degrees on crank shaft to the TDC/timing marks transposed above. Will need to crank a few rotations to get fuel to injectors.

There is a two to one ratio between crank shaft and pump, crank turns twice for each pump gear cycle. There are about 80 teeth on the pump gear, or about four point five degrees, times two for two to one ratio, so each tooth represents about a nine degrees of advance or retardation.

Remove pump and rotate gear in right direction (50/50 chance in my case,) rotate pump shaft to aligh key way ( easily said) and assemble and see how you did.

When you think you have it, put injectors back in and try cranking.

In my case I was still one tooth off. The engine would start but when the initial advance went away from the wax cylinder device, the engine would stop. So I had to disassemble it all and move one more tooth.

Then you time the engine by rotating the pump in its mount.

If this all sounds tough, and time consuming, and difficult, all I can say is that is an understatement.

Figuring it out and then actually doing it took two guys two long days. I could now do it in eight hours with a real good helper.

Charles Atlas would make very good helper for I must have put the engine through two hundred cycles using the socket set. It was interesting to see the injectors work. We would see smaller surts of fuel occasssionally, and if you went too slow you would miss the spurt for your injector. Had to throw the crank pretty hard. So you needed to pay attention to get the right spurt. Once you see it, it is very distinct, but not having seen it before you need to be aware.

[Charlie]

Thanks for sharing the procedure. It does sound tedious.

[sigmasailor]

Way to go. I'm sure you had fun. I hope you have learned something from the whole ordeal as well. I like the approach you followed. Very practical and without the need for special tools.
Look at this from the bright side; you managed to recover from a situation even Yanmar declares almost impossible to recover from.

[hpeer]

I've been reading Churchills history of WWII, 4500 pages. It has been an inspiration in determination when faced with a seemingly overwhelming foe.

Off again tomorrow, back to my voyage and out of touch.

I'll be making Newfoundland for sure and am hoping for Greenland.

Cheers

[DeepFrz]

Bon Voyage