Adjusting the Governor nut on a IGM10

I

ianwoods

Well-Known Member
Joined
26 Apr 2006
Messages
74
Visit site
I discoverd that a previous owner had been at the Fuel Injection Limiter nut just below the oil filler cap. I had cold starting problems since buying the boat over a year ago and have tried many many solutions to no avail. A mechanic friend today noticed the security wire had been removed and suggested that the control lever wasnt moving back far enough to let enough fuel through for start up. The engine always took about 30 seconds of cranking then fired in a lame hunting manner for about 10 secs till it gathered up. He wound out the governor screw a fraction and the engine fired in a couple of turns from cold and ran all be it a bit smokey.
How critical is the adjustment on this screw to get the engine to start from cold and run without being sooty? Anyone attempted to solve the effects of a previous meddler successfully?
 
How critical is the adjustment on this screw to get the engine to start from cold and run without being sooty? Anyone attempted to solve the effects of a previous meddler successfully? .

Seems you are playing with the fuel limiter setting which in ideal conditions should be set at the point where the engine is just about to make coloured smoke on application of load.

Are you sure there is not another device in there to allow more movement for an initial cold start similar to the button on the Volvo MD2 etc..

It seems you have to compromise between a good cold start and black smoke under normal running or lousy cold start and clear exhaust. ????? MAybe need to speak to Mr Yanmar.
 
Here was someone elses solution....might be worth checking your bleed screw.

..............................



So we started to think that the fuel pump might be okay, and that the bleed screw was cracked or stripped or something (there was some evidence to support this). So we hooked the mechanical fuel pump back up, bled the lines again, and she started and ran fine using the old pump.

So our conclusion is that the fuel pump is probably fine, that in fact the bleed screw is damaged and was the reason that the air got in to the lines. We figure it was a slow leak, hence the problem only showed up when we hadn't started the engine in three weeks. I will probably end up tapping a new bleed screw into the fuel filter housing, but in the mean time we just glopped a wad of RTV onto the top of that bleed screw to try and seal it up. Seems to be fine.

Bottom line: I thought I had bled the air out of the lines, but I hadn't, or I hadn't done it at all of the correct points. And diesels almost always have some type of a fuel problem if they won't start!
 
Ian

Page 4.10 of the manual explains this. All this nut does is limit the no load speed by acting as a stop on the regulator (throttle) to prevent the engine exceeding max speed when not under load. It is set at the factory and wired up so it is not disturbed. Does not affect fuelling on start up. Not sure how you reset it if it has been played with other than running the engine at full throttle without load and screwing it back in to limit revs to 3600. Tricky if you don't have a rev counter hooked up. In practice it is irrelevant if you never run at full throttle ie with the fuel rack right out, in neutral.
As I suggested in the previous thread, don't think the poor starting is fuelling related. Assume you have also had the injector tested and cleaned, plus a compression test. 1GMs have been known to bend con rods if they get water in them or run backwards (which is rare but possible). Can also be caused by worn valves not seating properly. Low compression can lead to poor starting but OK running.
 
Hello again. The nut that was adjusted is the huge nut with a domed end cap covering a fine adjustment nut rather than the the smaller limiter nut on top of the oil filler box. This nut allowed the lever to move further away from the rack and so allow more starting fuel. I will this evening see if the engine will cold start with this slight adjustment described. Ian
 
Ian
Got confused because of your mention of security wire. The injection limiter and its adjustment is covered on p 4.9 (section 2.1-2.3) of the manual. And yes, this does affect fuelling as it adjusts the static position of the rack. When I reassembled mine I set it exactly according to the diagram in the manual.
Hope this helps
 
Sure it's not the mixture adjustor?

........................................................................


It is a diesel and not a petrol so no mixture adjuster.


There are three adjustments on a diesel governor


1....Low speed limiter


2....High speed limiter


3....Maximum fuel (not same as high speed)


In this thread at times both 2 and 3 are being referred to in the same breath so beware of confusion as it seems they may be in near proximity of each other however it is 3 that seems to need being adjusted and not 2........(Speed as suggested in one case.
 
So does anyone know the 1GM10 well enough to point these 3 adjustments out? I assume 'low speed' is the 10mm nut at the engine end of the cable? What about the other two?
 
This diagram may help...

This diagram from the workshop manual may help.
1GM10governor.jpg
 
I spent a long time with a poor starting/running issue on a 1GM. I fiddled with the adjuster, I even broke it because it is a hollow shaft with a spring in it and I forgot I still had the locknut tightened on it.

Eventually I realised that the real problem was that when it is cold, the 1GM engine can be stalled by its alternator if the battery is healthy but not fully charged.

Having the injector serviced, or carefully cleaning the carbon off around the little pin can also make a great difference to cold-starting - my engine got harder to start recently until I swapped for my cleaned-up spare injector..
 
Hi, I had the injector serviced.
Have you got any tips about setting the position of the large "Fuel injection limiter nut" as shown on the previous posting - so as to stop smoking? Screw in/out? How many turns? etc.
 
Re: This diagram may help...

Many thanks for the diagram. Do you have any information on how to get the optimum setting for the Fuel injection limiter nut? /forums/images/graemlins/ooo.gif
 
Re: This diagram may help...

Do you have any information on how to get the optimum setting for the Fuel injection limiter nut?
.............................................................................

There is probably a 20 page procedure for this however the correct position will be where there is just a trace of smoke under full aceleration and cold starting is OK The more OK you make it for cold starting then the more smoke you will have to control against under load.

I am more familiar with Volvos where these adjustments are easily reached from outside. I gather this adjustment is inside the oil filler opening so a danger of dropping things in /forums/images/graemlins/smile.gif There for beware doing it with engine running.

I think looking at the drawing it will be screw outwards for more and in for less.
 
Hello Tranona, I have had a look through the manual that I have but cannot come across the section you mention - maybe a different book. Do you have any info you could post
re resetting the Fuel injection limiter screw as shown on the posting of pvb. Thanks
 
Re: This diagram may help...

[ QUOTE ]
Many thanks for the diagram. Do you have any information on how to get the optimum setting for the Fuel injection limiter nut? /forums/images/graemlins/ooo.gif

[/ QUOTE ]Firstly, there's a bit of confusion over workshop manuals, and it seems that different manuals are being quoted. I've no idea which is the definitive manual, but there's a 240-page one here for free download (60MB file!). Secondly, I'd be very wary about fiddling with the fuel injection pump settings. If you don't know exactly what you're doing you could make the situation worse, or even damage the engine. The manual I've seen doesn't give any guidance on these adjustments, in fact it says....
1GM10adjust.jpg


I reckon if you've tried most things it would be worth your while paying a Yanmar engineer to look at it. For what it's worth, I still think the symptoms you originally described are classic signs of a slow air leak into the fuel line.
 
Re: This diagram may help...

Hi Ian
Yes, If you look thru the filler hole, you will see the fork for the governorlinked to a pin in a slot in the side of the injector. The pin is part of the fuel rack as you can see from the exploded diagram in the earlier post. Where the rack comes out of the front there is a dot, or probably a punch mark. This has to be set so that it is just fully exposed from the face of the pump. Note that where the rack comes out there is a cutout in the face. The reference face is the cutout, not the main face.
Instructions to adjust (2.3 in the manual)
1 Set the governor lever to the free position
2 Remove the injection control shaft cap nut (dome), loosen the hexagonal lock nut, and loosen the injection control shaft (a hollow tube threaded into the lock nut) so that the spring inside is disabled.
3 Move the governor lever to the left until the rack and the injection control shaft touch lightly
4 Set the governor lever to the free position and push the rack by slowly turning the injector control shaft clockwise
5 Align the center mark of the rack with the reference face
Lock the injection control shaft with the hexagonal nut and cap nut.

Sounds complicated, but like all these things becomes obvious as you do it.
 
Re: This diagram may help...

For what it's worth, I still think the symptoms you originally described are classic signs of a slow air leak into the fuel line.

*************************************************

Wel those were my thoughts as well initially and probably if fitted then the primary fuel filter ...
 
Re: This diagram may help...

Hello Tranana, Today engine reluctant to start. but it fired up in the end 40 secs. Very smokey. Adjusted the limiter nut which lies beneath the dome inwards till smoking stopped at 2500 revs when under load. I think I have the adjustment to within a cats wisker. Mechanic in the boatyard, who knows little about yanmars, thinks that compression can be the problem. Based on idea that a gale is coming out of the oil filler cap when the engine is running. A friend said "Rubbish" you would expect that with a single cylinder - but not a twin - for where would the air in the crankcase to go every time the piston descends. In a twin one goes up as the other goes down so ther is space for dispaced sump air". On Monday this mechanic is to do a compression test. So here we go again.
Incidently a learned one suggested that the sump oil in the sail drive leg ought to be 10-40 engine oil not the SAE 90 as listed on the filler cap of the Saildrive leg - this is to reduce drag on starting. Any comments anyone?
 
You must log in or register to reply here.

Share this page

Top