Yanmar 2GM20 Injector pump delivery problem

[broken pete]

Originally Posted by Richard Kollmann

Think about it if timing is off flow is too early or too late on both cylinders. One cylinder's flow off can be a single cylinder pump adapter's incorrect torque adjustment. At 2000 rpm trip one compression release at a time to isolate the cylinder. Then adjust adapter torque to reach best matching rpm fuel.

Thanks Richard, but what do you mean by "adjust adapter torque" what adapter are you referring to and what torque setting do you mean.
Thanks again

[broken pete]

Originally Posted by wannacat

Just wondering, you did drain , clean the tank, fuel filters and are using fresh new diesel fuel?

Yes absolutely. Tank was cleaned out and emptied, lines blown through, new fuel and filters throughout. The boat was on the hard for over 8 years with both engines ceased up, the one im working on had a head gasket failure from overheating and was left to sit in that position. amazing how some people just don't care.

[broken pete]

Originally Posted by skipperpete

Is the 2GM fitted with a higher output alternator and/or a smart regulator? Even the original hitachi alternator will create a lot of load at low rpm if the regulator fails and the result can be slow acceleration and black smoke . To prove or disprove this possibility just remove or loosen the belt and run the engine briefly. The coolant circulating pump will not be working so you have about a minute or two to complete the test before the temp starts to climb.

The alternator on there is charging at 14.10 volts, at least that was what I saw on the voltmeter when I was testing her. That was just a quick glance so its possible the alternator has an issue but at the time of testing I wasn't paying much attention.
I saw 14.something and figured it was working. it is a 60 amp alternator they have on there but the batteries are fully charged because the battery charger is running.

[broken pete]

Just an update on the issue for those helping me out..... Today I ran the engine again (its a slow process because I need another person to spray water into the raw water strainer).

The engine nailed a bit for the first 10 seconds and then settled down. I have discovered the small fuel filter that is mounted on the heat exchanger had some crap in it, I am now wondering if that is causing a fuel starvation. So tomorrow I will hunt for the filer element and try again. Failing that I will get that injector pump calibrated professionally.

Will keep y'all updated

[Compass790]

Cheers for update,
hope it's just your filter. If your rack mark is right & i know you said you got it right It should be injecting the right amount of fuel.
Did you check the timing? I would do that before taking pump in for testing.

[broken pete]

Originally Posted by Compass790

Cheers for update,
hope it's just your filter. If your rack mark is right & i know you said you got it right It should be injecting the right amount of fuel.
Did you check the timing? I would do that before taking pump in for testing.

Yes I am 100% sure the rack was correct when building the pump, the little red marks make it quite straightforward thankfully.

I will take your advice and slacken off the pump slightly if this doesn't work, but I will keep the thread updated.

These small engines are amazing, so robust

[wannacat]

You did say that you did drain, clean the tank, new fuel filters c/w new fuel and yet you discovered "some crap in it". Now you've got to wonder where it came from and how it was missed? Is there more somewhere? I assume you seen the bottom of the tank when you pumped out all the old diesel? Blowing the lines only proves they're not blocked, there still could be lots of gunk in there after 8 years of sitting. Are they metal or flexible lines? Were the pre filters [raycors or whatever] dirty also? It usually is a short distance from them to the small filter on the engine. If the pre filters are clean then I would take off the line from them to the small filter and blow them out, spray some brake fluid in it first to loosen any gunk, then blow them out into a rag and see if you catch crap. Then replace and start her up with a new filter again.I wouldn't be spending money on the pump yet especially since it seems to start easily for you. Eliminate the simple thinks first.

[broken pete]

Originally Posted by wannacat

You did say that you did drain, clean the tank, new fuel filters c/w new fuel and yet you discovered "some crap in it". Now you've got to wonder where it came from and how it was missed? Is there more somewhere? I assume you seen the bottom of the tank when you pumped out all the old diesel? Blowing the lines only proves they're not blocked, there still could be lots of gunk in there after 8 years of sitting. Are they metal or flexible lines? Were the pre filters [raycors or whatever] dirty also? It usually is a short distance from them to the small filter on the engine. If the pre filters are clean then I would take off the line from them to the small filter and blow them out, spray some brake fluid in it first to loosen any gunk, then blow them out into a rag and see if you catch crap. Then replace and start her up with a new filter again.I wouldn't be spending money on the pump yet especially since it seems to start easily for you. Eliminate the simple thinks first.

Absolutely, I should clarify.

The tanks were completely empty when I got the boat, I used a USB camera to learn this. The tank is not massive so easy to see.
The pre-filters (racor style) were horrible so I striped them completely, degreased and pressure washed all the tiny parts before them back together with new filters. The lines are all flexible fuel lines upto the small yanmar filter where it becomes a short braided hose. I use a scuba tank to blow them through.

The small yanmar filter had a bit of crap in the tube that goes to the steel braided flexible hose to the injector pump. the part of the housing at the top. That outlet was partially blocked and is where I found the crap.

Maybe there has been a restriction in the flow, I kinda hope so. Will let ya know

[Compass790]

Originally Posted by broken pete

Yes I am 100% sure the rack was correct when building the pump, the little red marks make it quite straightforward thankfully.

I will take your advice and slacken off the pump slightly if this doesn't work, but I will keep the thread updated.

These small engines are amazing, so robust

No I didn't say slacken off the pump ( unless you mean blame wise). I asked if you had checked the timing? Follow the workshop manuals instructions

Yes you want to check the simple stuff first before blaming the pump. If you take it into injection specialist you could find they want to rebuild yr rebuilt pump. Just trying to help you save money.

[Wotname]

Originally Posted by broken pete

Thanks Richard, but what do you mean by "adjust adapter torque" what adapter are you referring to and what torque setting do you mean.
Thanks again

I note Richard hasn't gotten back to you yet; I believe he is referring to the adapters at the top of the injection pump (circled in red on photo of my previous 2GM20). Depending how much you tightened the adapter, it has a small effect of timing or so I'm told. However I can't vouch for the veracity of this claim.

[skipperpete]

The circled part in the photo is the delivery valve holder and has only one torque setting ( tight) however, if the injection timing needs to be checked or adjusted , the delivery valve inside this fitting needs to be removed to ascertain the precise point of injection by indicating spill cutoff. Best to read the manual for the full procedure and get a clear idea of how to go about it.

[motion30]

Has the bottom and running gear been cleaned?

[broken pete]

Originally Posted by motion30

Has the bottom and running gear been cleaned?

Are you referring to the bottom end of the injector pump? If so, yes, the pump was stripped apart completely, every part cleaned and checked before re-assembly.

[Compass790]

Originally Posted by broken pete

Are you referring to the bottom end of the injector pump? If so, yes, the pump was stripped apart completely, every part cleaned and checked before re-assembly.

I Think he means the boats bottom & propellor as that can cause those symptoms