The Universal M25 is winning the battle

[Simi 60]

Originally Posted by Quadrille in JB

My M25 will not start on WD-40. When it’s cold it won’t start unless the glow plugs have been held in for at least 20 seconds. It acts exactly like the OP described. It sounds like the glow plugs are working from the amp draw so my best bet is bleed the injectors, thoroughly. And make sure you use the glow plugs before each starting attempt. I’ve had the same problem After replacing my fuel filters.

Don't they gave a small facet style 12v pump for fuel?
We have never needed to bleed as the fuel pump sorts that out.

[Tetepare]

Oh another thing. My c30 glow plug switch was two position, on and heat. When it got gummed up over time it would feel like it was all the way clockwise, but wasn’t. The audible drop was the give away. Spray some lube in the switch and work it a few times.

[Quadrille in JB]

I also have an electric fuel pump but that just provides fuel to the high pressure injection pump. The high pressure fuel line nuts on top of the fuel injectors need to be loosened and the engine spun over until clean fuel comes out with no bubbles. Tighten one injector nut ar a time while cranking the engine until it starts. Rinse and repeat.

[Ballsnall]

Originally Posted by Madehn

Spray wd40 in the intake while cranking. If it fired or runs briefly you have a fuel issue. If it doesn’t perhaps you have a compression issue.

Ether is the better option.

[donradcliffe]

Thanks so much for all the good advice. I will try to get down to the boat today. I will check the muffler, and give it a shot of ether. If it catches and dies, I will tear into the fuel supply system.

[Cap Bill Des]

Our M25 was very reliable(we we living onboard and cruising full-time), and then one day it wouldn't start and stay running. After three hours of checking and taking things apart....we found a failed check valve in the exhaust system! It was a "flapper" check valve built into a section of rigid steel pipe, that itself was between two sections of hose between the exhaust elbow and the waterlift muffler. The little pin that allowed the flapper to pivot just finally let go and the flapper was jammed, obstructing exhaust flow. The engine couldn't "breath" freely with this obstruction. It would crank and pop but not start because it could not exhaust well enough. We removed the flapper and all was well !

[jarin]

Just curious if you have sorted out your M25? I'm having similar issues on mine. I changed to the upgraded alternator bracket and put on a new alternator while I was at it. After filling and burping coolant the motor was running fine although I did notice when in gear the motor seemed to bog down a bit compared to normal.



Few minutes later it turned off and I haven't been able to get it started since. I've checked and cleaned the fuel uptake pipe, replaced both fuel filters, replaced the fuel injector lines and have done my best to bleed the system according to info found here.



The glowplugs are getting voltage and do get warm but I didn't measure amperage. I've emptied the muffler and closed the fresh water seacock when cranking and it does kinda sound weird now compared to normal. This is my first boat and first time working on diesel engines so it is possible that I have screwed something up I guess.



https://streamable.com/gx23g6

[Piratenorm]

My fix was as simple as removing the screen from the fuel pickup hose in the fuel tank. It had become clogged and was preventing sufficient fuel. This was discovered After I did everything already mentioned. And speaking of that hose, it’s a hard plastic on an ‘83 (mine was an ‘83) and over time it became brittle and had developed a crack. Once the fuel in the tank went below that I sucked air and she died. Replaced it a proper copper line into the tank ( no screen) and nary a problem since. Good luck.

[GrowleyMonster]

Air intake is unobstructed?

[donradcliffe]

Its still winning. The boat owner/helper took off for Europe.

The muffler was empty. A shot of ether made it stop cranking and I don't want to damage it by throwing more amps at the starter.

I did find what looks like a compression release lever in the lower left hand corner of this picture.

When I get a helper, I think my next move is to change the fuel filters, then take a downstream fuel line off and make sure there is adequate flow with the electric fuel pump, then bleed the hell out of it. I will There is no bleed valve, so I will have to let fuel dribble out of the bolt on the inlet of the injection pump.

[Stu Jackson]

Originally Posted by donradcliffe

1. ...I think my next move is to change the fuel filters, then take a downstream fuel line off and make sure there is adequate flow with the electric fuel pump, then bleed the hell out of it. I will


2. There is no bleed valve, so I will have to let fuel dribble out of the bolt on the inlet of the injection pump.

1) Have you considered the information in my reply #3?


2) That seems odd. There should be a knurled knob at the inlet to the injector pump. It is there for that reason. The M25 is one of the simplest diesel engines to bleed.


This may help or serve to confuse you even more.


https://c34.org/bbs/index.php/topic,....html#msg62710

[skenn_ie]

Is there a governor ? If not, you will likely require the throttle to be fairly well open for starting. A governor will do that within the pump. You could also "crack" the injector pipes at the injectors and see if it blows anything, bubbles or fuel, when cranking. If anything other than fuel, there is air in the system which needs to be cleared.

[donradcliffe]

Originally Posted by Stu Jackson

1) Have you considered the information in my reply #3?


2) That seems odd. There should be a knurled knob at the inlet to the injector pump. It is there for that reason. The M25 is one of the simplest diesel engines to bleed.


This may help or serve to confuse you even more.


https://c34.org/bbs/index.php/topic,....html#msg62710

Yes, I've got the hex bolt, and will try to catch some of the spilled fuel in a cup.

My plan is to change both filters and pull the fuel line of the IP inlet and turn on the electric pump. If the fuel comes out strong at the IP, with no bubbles it will eliminate the ball valve problem and the clogged inlet as causes.

[donradcliffe]

Originally Posted by skenn_ie

Is there a governor ? If not, you will likely require the throttle to be fairly well open for starting. A governor will do that within the pump. You could also "crack" the injector pipes at the injectors and see if it blows anything, bubbles or fuel, when cranking. If anything other than fuel, there is air in the system which needs to be cleared.

There is a governor, but after I bleed up to the IP I will open the throttle wide and crank until the injector pipes start squirting. They were squirting before, but it might have been water/fuel.

[NNBill]

Originally Posted by Stu Jackson

1) Have you considered the information in my reply #3?


2) That seems odd. There should be a knurled knob at the inlet to the injector pump. It is there for that reason. The M25 is one of the simplest diesel engines to bleed.

https://c34.org/bbs/index.php/topic,....html#msg62710

I've worked on quite a few marine and industrial Kubotas, and there doesn't seem to be much rime or reason as to which had the bleeder valve which went up to the injector return line and which had the bleed down the side of the engine bleeder bolt.