Yanmar 3GM30F - Injection Pump sensitivity -Help?

[Scott T-Bird]

As I've said before, I'm taking my gear case off to replace the gasket and hopefully repair an irritating oil leak. To do this I have to take the fuel lines off so that I can lift the injection pump body clear from the gear case. I definitely don't want to do too much because the timing appears t be very sensitive and I don't want to open a can of worms!

I started to loosen the nut that connects the high pressure fuel lines on the first delivery valve. I found that I needed to hold a wrench on the delivery valve spring holder to keep the assembly from turning, which was bending/crimping the line. So I got the first one off and realized that I would need to remove the spring holder to get a wrench on the 2nd holder. After I got the 2nd line off, I found that I could get the 3rd line without removing the 2nd holder.

So that part is good but I got a little curious about the components. I lifted out the delivery valve, the packing, and the valve holder.

I see there are some tests I can perform to verify if the delivery valve is functioning well. You can see there is a lot of debris to be cleaned off the engine. I was able to lift that particle out with a tweezers that you can see in the photo below. But I'm worried about infecting the system with dirt by opening each of these valves. Other than the one that I pulled apart, I don't have to open the other 2. Is it worth opening and checking the condition of the valve, the delivery spring and the valve holder, or is something I shouldn't touch if not necessary.

I'm most concerned about messing up the timing. The instructions say that the timing adjustment shim under the pump body is critical and a lot of care has to be made not to mess it up. Also, the parts can't be miss-placed from one injection to the other and the plunger shims in particular should not be changed. To mess it up means having the pump adjusted offsite with a injection pump tester. I don't want to go there ... I know that the delivery valve and the holder have to be paired so I would be careful not to mix any pairs.

 

[jon hansen]

all copper 'crush' washers need to be replaced every time. that said, in a pinch you can heat them red hot with a torch and the washer will be reusable. they are cheap. i carry spares.

on my old perkins, if it ain't leaking oil, i know one thing for sure. it's out of oil.

english engines. well at least mine doesn't have a lucas fuel pump

 

[Michael Davis]

english engines. well at least mine doesn't have a lucas fuel pump

My Perkins has a CAV injector pump. I wouldn’t play with it unless absolutely necessary. The last time I had one rebuilt it was more than three boat bucks (cdn$)

 

[jon hansen]

2 years ago i had the injector pump rebuilt, last year was the injectors and starter. i run schedules, rebuilding gear that has time on it but ain' t broke is better/cheaper, "preventive maintenance."

the boys in green bay have all my rebuild records back to 81'.


..... but you still never know when she'll blow

 

[All U Get]

Here we go, my money is riding on the high stakes game of boat repair. Did Sue approve of this and/or did U-tube come out with a new DIY.

 

[dhjay]

You may well damage the shims while removing the injector pump. Just measure their thickness and purchase new ones and replace with like thicknesses. They come in a set and are not expensive.

 

[Scott T-Bird]

I did get the gear case off on Sunday but couldn't get the injection pump more than loosened. I wanted to at least take a good look at it, but I didn't necessarily want to do any part replacement or rebuild. I brought the gear case home with me and was frustrated after an hour not finding a way to detach the pump completely. I called a mechanic yesterday and asked for help. They were stumped because it sounded like I was going about it the right way. After hanging up, I adjusted the fuel rack just slightly and off it popped! No problem ... just slipped right off the studs nice and easy. I guess I was overly concerned about the fuel rack position and wasn't doing enough to adjust it to exactly the right position to free it up.

Actually, I thought the gasket on the case was going to show an obvious defect, but it didn't really look bad. I peeled off a bit at the top of the case. The mechanic said that it was more likely that the crank shaft seal was leaking a bit. Well, I'm replacing the gasket and the seals so it would be a moot issue at this point. I was concerned about damaging the shims, but I was told that it is best to simply replace them - just be sure I'm replacing in kind. They were a bit crumpled and the mating surfaces with the pump need to be cleaned anyway. It should be relatively easy to put all this back together. A lot of cleaning is needed and I'm simply replacing a few of the parts that have some corrosion.