32-2 M-25 diesel no start stumped

[Soupy sails]

I have good crank. I have changed filter and have bled air from system up to the knurled knob getting a good flow. I'm thinking at least one cylinder would fire I get nada. two things I don't know if they are relevant. One is that there is an arm bracket at the rear of the engine looking aft, that has a spring attached to it that spring is broken I think it somehow adjusts the valves while the engine runs but I'm not sure I haven't found any info in the manuel. The other odd thing is I made the glow plug change early last winter and It's possible that I have wired to the wrong post but it's warm today and I'm not using the glow plugs anyway and since I have a good crank I'm thinking that's a wrong solution for the starting issue. Looking for Ideas from the family.

Thanks,

Dan

 

[Soupy sails]

Found the spring in the parts book I think it's the decompression spring. Now the question is does anyone know what position that lever is supposed to be in? If it can be described?

 

[Tin Kicker]

The factory owners manual is about 3 pages into the tab marked "Resources"

 

[Kenneth K]

Here's a picture of the M25 decompression lever. The normal (compression) position of the lever is shown (lever to stbd / no spring tension). Lever to port (full spring tension) is for decompression.



The lever should NEVER be moved while the engine is running. It is typically only used for starting (cranking) a very cold motor or when battery voltage is marginal for cranking.

The lever should only be held in the full closed (compression) or fully open (decompression) position, again, with the latter only used for cranking. The lever is not used for any in-between positions for adjusting the valves.

The spring holds the lever in the full closed (compression) position. If your spring is broken, I would just wrap a small wire or zip tie to keep the lever in the compression position until you get the spring replaced. The spring is not required in the "compression" position so you could just leave the lever wired closed. The spring is only used when cranking a cold engine, so when the engine is cranked up to speed (with no compression), the lever quickly snaps back into position when released, allowing the engine to start.

For your particular non-start issue: Try the glow plugs. At my first launch after getting the boat, it took me two hours to get the motor started. I was holding the glow plugs 15-20 sec as I had read somewhere. With the old, original wiring setup I had at the time, it actually took more like 30-40 sec to get a cold engine started. Since rewiring the circuit and installing a glow plug relay this season, I now use 10-15 sec glow time. But, I find that less than 10 sec = weak start up (multiple engine turn-overs before starting) while 15 sec = engine immediately roars to life.

 

[Soupy sails]

Thank you Ken,

The information on the compression lever is very helpful. I will have to wire it open since I don't know where I can get this spring until I get back home. Too late on the warning not to move it, while cranking the engine I moved it to different postitions trying to figure out where it was supposed to be set. I won't make that particular mistake again and hopefully I didn't damage any valves or lifters. Time will tell.
As to the glow plugs that's a good tip I'll start don that now but I was thinking that if the fuel was not sucking air that the cylinders would heat on their own since it's pretty warm today but at least you've given me a path to work I'll let you know how it works. My plan will be to pull them out and check to see if they're working properly. One issue I forgot to mention was that there has been a symptom I've been wondering about. On start I push the glow plug switch for 10 seconds then when pushing the start the volt meter swings to 0 and the starter goes blank. I'm thinking it's a short somehow from the glowplug to the starter switch but I haven't been able to find it yet.

Any how thank you again for your tips I'll start working on them.

Dan

 

[supersailor]

Do your glow plugs to see if they are all working. Without glow plugs, the engine can take a long time to fire. If you are cranking for a long time, turn off the raw cooling water so you don't flood the engine exhaust with cooling water. Don't forget to turn it back on when it starts. Also make sure the fuel supply is coming in clear and without bubbles. I had this problem once and it turned out to be an internal crack in the fuel filter that was letting a string of bubbles into the fuel stream.

 

[Christian Williams]

Try again to bleed air, including downstream from the bleed valve.

Loosen the fuel line to an injector, turn over the engine with the starter, and you should see fuel spurt out (small amount). Then retighten Do that with all three injectors. Here's a video. Service Department Vic also explains the decompression lever.

 

[Kenneth K]

You wouldn't have damaged the engine by moving the compression-release lever while cranking. That's what it's there for.

The damage is caused by opening the lever on an engine that's already running. The release in compression on a "firing" cylinder would likely over-speed the engine.

 

[Soupy sails]

Thanks Christian and Bob,

So I checked the glow plugs reisitance was 1 on each so they look good with out pulling them. While pulling off the lines in my minds eye I see a couple of you laughing a little when I realized that removing the center one would I would have to loosen the intake manifold. Ah the pure sense of accomplishment when I dropped the nut from the glow plug under the block. Maagnets are a real miricle ne'

Thanks again,

Dan