New Member with Question about Yanmar Diesel

[calphi27]

Well after joining a landcruiser forum, I decided to find one for sailing. So here I am. I have been looking all over the site, and you guys have some good stuff on here. So here is my question.

I have a 1990 Thomas 35 sailboat with a 3GM20F Yanmar engine. I am trying to replace the fuel injector pump, but am having trouble removing it. It seems to be held in by some sort of rod.

I called 2 yanmar mechanics about this issue. One said something about the throttle being 1/2 way then pulling the rod out, and the other said something about an inspection plate. They were not very clear on what they were saying, so that is why I am asking this forum.

I just ordered the seloc manual and am looking for the yanmar manual on this engine. Where is the best place to buy the yanmar one?

Thanks in advance,
Matt

[Chief Engineer]

Why are you trying to remove the injection pump to begin with?

Originally Posted by calphi27

Well after joining a landcruiser forum, I decided to find one for sailing. So here I am. I have been looking all over the site, and you guys have some good stuff on here. So here is my question.

I have a 1990 Thomas 35 sailboat with a 3GM20F Yanmar engine. I am trying to replace the fuel injector pump, but am having trouble removing it. It seems to be held in by some sort of rod.

I called 2 yanmar mechanics about this issue. One said something about the throttle being 1/2 way then pulling the rod out, and the other said something about an inspection plate. They were not very clear on what they were saying, so that is why I am asking this forum.

I just ordered the seloc manual and am looking for the yanmar manual on this engine. Where is the best place to buy the yanmar one?

Thanks in advance,
Matt

[never monday]

STOP>>>>>
The injection pump is almost never the problem.

Also, there are brass shims, not gaskets under it.

What are the symptoms?

[calphi27]

I am removing the injector pump cause it does'nt work. I've changed fuel, bled the lines, and when I crank the engine to bleed the injector pump, I get no fuel out the top, and therefore no fuel over to the cylinder heads. Whats holdind the pump down? Yanmar told me there was an inspection plate, which is BS! There is none. I plan to have the pump rebuilt. Help!! thanx

[Alan Wheeler]

It is possible the pump is still OK. The pump has a fuel rack that determins the dose of fuel. If that rack is shut hard off for some reason, you will not get fuel. I am best to let Pat go further on this, as I have not been inside the yanmar pump. He has.

[never monday]

First I need some info to set the picture.
Was the reason for changing everything maintainance? or did the engine stop running? You said it's a 3GM20F. That's an engine that's not listed in my manual. Can you confirm if it's a 2GM20F or a 3GM30F please. What filter/water strainer is mounted between the engine and fuel tank?

[never monday]

add to the above,
Does the throtle have it's normal travel?
does the cut off cable have it's normal travel? does it spring back correctly?

[calphi27]

The engine did stop running. There was a typo earlier and the engine model number is 3GM30F. I will have to check on the filter/water strainer next time I am at my boat. I have checked the throttle and cut off, and they seem normal. It does spring back.

[never monday]

Just to confirm, you have positive fuel pressure at the bleed screw on the injection pump? The fuel pulses with every stroke of the priming pump?

[never monday]

Originally Posted by calphi27

It does spring back.

That statement alone makes me what to encourage you NOT to remove the injection pump.

[Pa La O La]

HEY,

Hope you are having better luck. I have a 3GM30 in my Prout. I have had the whole system out and back in and I even got it running right again. There is a plate for access but it isn’t all that easy to get at and use on mine. But it is a must to find and use. It is the plate where the idle adjuster bracket is. It has a curved end that goes up against the regulator lever. You have to make sure you get the rack reinstalled right or you could suffer a runaway and no way to stop the engine. That is a bad thing. The fuel control rack is what is hanging up on the governor lever inside. Re building the pump isn’t much of a DIY project. There is quite a test machine to tune the monster in. When you reinstall you have to use the shims to set the timing.
Good luck. You can email me if I can give ya any other help.
(If this was any help)

Gary

[calphi27]

Thanks guys, I really appreciate all of the input. The engine is a 3GM30F, made in 1990. It ran very well for yrs, but now will not start. Yes, the priming pump works fine and I can get fuel all the way up to the bleed screw on the injector pump. It pulses with each pump of the primer pump. I have a Racor in line filter between the fuel tank and the engine. I changed it. I also changed the fuel and cleaned my tank out completely. I installed a new fuel filter on the engine. I bled the lines all the way up to the injector pump. But when I crank the engine I no longer get a squirt of fuel out the top of the injector pump, like I used to. I just assumed the pump was bad? The throttle cable works fine with normal travel. The cut off cable works smoothly, as I replaced the cable last year. It seems to spring back fine. I am completely perplexed. Any other thoughts? Thanks again!!!! calphi27

[never monday]

Crack the injector lines loose 1-2 turns at the IP. crank the engine over with the compression released. You should get a squirt starting fairly quickly. those pumps can air lock and be difficult to bleed.

[calphi27]

Thanks, Pat. I have cracked the injector lines loose at the IP. I have cranked the engine several times and still get no squirt. But I have not done it with the compression released. I'll try it that way. What is the fuel rack, Alan mentioned? Could that be it? Thanks again!!

[Ex-Calif]

Originally Posted by never monday

Crack the injector lines loose 1-2 turns at the IP. crank the engine over with the compression released. You should get a squirt starting fairly quickly. those pumps can air lock and be difficult to bleed.

That's sorta what we had. Fuel all the way to the injector pump and I was too "scairt" to crack the injector nuts. We cracked them at the injectors. Did that and she fired right up. (Volvo BTW)