Yanmar 1GM10 Difficult to Start

[roboandkate]

I have a 1GM10 that must be at least 15 years old now, last season it started to get difficult to start, it would fire but wouldn't pick up, once running it was ok.

Over the winter I emptied the fuel tank and refilled it with white diesel from a petrol station, changed the fuel and air filters, bled the system and it's still the same.

I though an injector rebuild might not be a bad idea but it wouldn't come out, even running the engine with the nuts slackened.

The fuel pump appears to be pumping ok but there doesn't appear to be a lot of fuel coming out the far side of the govenor, and no fuel going back up the return pipe even when I get it running.

Any ideas that doesn't involve stripping the engine down would be appreciated.

 

[pete]

My 15year old 1 GM10 became bad to start after the winter layup last year and after a lot of checking over a month or so it turned out to be a linkage between the governor and the injection pump sticking and not giving it extra fuel for starting, when it did start all was well until the next cold start, This linkage has a spring on it and can be tweaked through the oil filler hole with your finger (engine off).
btw my engine does not return diesel from injector to the tank and I was told some injectors only return fuel when they are getting worn.
Hope this helps
Pete

 

[corncob]

When trying to start do you see a lot of blue/white smoke, or any smoke? While trying to start, did you spend long periods turning it over?

Try coating the injector with WD40, and leave it overnight. remove the holding studs match a spanner to the two flats on the injector, and try and twist it loose, it should come out? When reassembling coat the injector with anti-seize compound, should make it eaiser next time you need to remove it.

 

[boatmike]

I agree thats a likely cause, but you need to persevere with getting that injector out. Try again when the engine is hot....

 

[corncob]

It could well be the cold start system. When the engine is shut down a spring on the governor shaft pushes the fuel rack on the injection pump to an excess fuel position, for cold starting. When the engine is started the governor pulls the fuel rack back. Check through the oil filler cap, you will see the injection pump and fuel rack, when the engine is turned over you will see it pull back, when the governor takes control. The time at which the fuel rack is held in excess fuel is determined by the spring, if the spring wears, it will allow the fuel rack to be pulled back to early, thus effecting cold start performance. I would not look in this area until you have determind that the fuel system is fully functional and you have checked compression (max 470PSI min 390). You have not had any water through the engine have you?

 

[SteveB_Sigma33]

May not help at all but I completed a head overhaul on my Penta 2002 because I had the same problem of starting when cold. On mine the exhaust valves were pitted to my compression was down as these were not forming a good seal.

After working with a friend of mine and a local garage managed to do the job really cheap (didn't involve anyone from the marine industry other than getting replacement gaskets).

The engine now starts on the third crank from cold.

 

[bob_tyler]

Moral - replace with a Beta. After 5 months laid up it started on the first turn of the key on the first compression stroke!

 

[roboandkate]

Thanks for all the comments, I'll certainly have a look at the fuel rack set up, does anyone know where I can find a diagram so I know what I'm looking at?

Also if I take off the governor to injector pipe and wind the starter motor over should the fuel hit the cabin roof or just dribble out?

Re getting the injector out I think with this one it would have to be on the bench before you stood any chance, I've tried all the normal ways, problem is to take the head off it means taking the engine out and I think that will be the end of it so I'm a bit reluctant, especially if I can get anotther season out of it

 

[steve28]

You fuel supply will vary according to where the throttle is set, it seems no one has mentioned this to you yet. I would only expect a dribble out anyway.
The injector has got an o-ring around the body to help stop any ingress of rust foreign objects getting down the sides. if it will move left and right i would try using a couple of open ended spanners to lever it upwards when its warm.

As for the fuel rack i doubt it is the fault, more likley to be the seat in the injector.

steve

 

[PIGLETSDREAM]

Our Trapper 500 has a 1GM10 and it started to become harder and harder to start.

I checked out this web site for great info

http://www.yanmarhelp.com/index.htm

On their advice replaced the water exhaust coolant bend as this had become very blocked.
Replaced/serviced injector
Took the head off and stripped and cleaned, including valves.


Started first time by hand after that, untill the hand crank lug broke off so now its by the key.

On the web site you will find drawings from the Yanmar Workshop manual.

All the best