M25 Diesel question

[Hogheaven]

Hi Guys,

what is this lever for on the back of the valve cover. Feels like it is pressing on something, the valves perhaps?

Regards,
Nels

 

[JohnVTX]

Pic doesn't work

 

[Stu Jackson]

It's the decompression lever. Don't bother with it. For some bizarre reason, the C30 guys have been using this as an excuse or "cover" for a poorly performing electrical system for the past three decades. I have not idea why, but Max Munger kept doing it in Mainsheet magazine.

You might be interested in this:

Engines 101 - The BIGGEST & BEST collection of M25 Series Universal Engine Information on the Internet, plus some M35, too

http://www.c34.org/wiki/index.php?title=Diesel_Engine

 

[Skipper]

You need to reattach that spring to it.

 

[mortyd]

have you considered investing in an engine manual?

 

[Stu Jackson]

Morty, if he clocked on the link I gave him, the investment would be 0.

Great offer, he shouldn't refuse.

 

[Tally Ho]

You need to reattach that spring to it.

My Yanmar 2GM20F does not have any springs attached to the compression levers....should it?

To the OP, the levers (there should be 1 per cylinder) release the compression in the cylinder. If your battery was weak, you could flip the levers, start the engine turning over, then close the levers. I have seen single-cylinder diesels hand cranked, with the lever open to get the engine turning over, then closing the lever to start the engine.

I never mess with mine.

Greg

 

[Stu Jackson]

My Yanmar 2GM20F does not have any springs attached to the compression levers....should it?

Greg,

I dunno. I have an M25 and it has the spring attached. You have a different engine, so there's usually no comparison. RTFM?

 

[woodster]

My Yanmar 2GM20F does not have any springs attached to the compression levers....should it?

mine don't and i have not seen any that do

 

[PineyWoods]

mine don't and i have not seen any that do

IMO every diesel out to have it, as it's a godsend if you have inadvertently depleted the batteries, or the toy wiring of the older Cats. have neutered them.
It saved our bacon once on our little 5411soon after we bought the '82 30 last year.
Pete

 

[Skipper]

The universals have the spring. Different design than the Yanmar. I mean, it's a completely different engine line :-|
The spring is hanging off its bracket in the op's picture.
The spring keeps the lever from rattling against the valve gear.

 

[mortyd]

stu, when i first got the boat i had terrible trouble starting my M25. after all kinds of useless advice i bought an engine manual, sat down and read it, and have not had any starting trouble since. at least 20 seconds of glo plug - right there in the manual.

 

[woodster]

IMO every diesel out to have it, as it's a godsend if you have inadvertently depleted the batteries, or the toy wiring of the older Cats. have neutered them.
It saved our bacon once on our little 5411soon after we bought the '82 30 last year.
Pete

so you will know i was referring to yanmars not m25s...... yannies have compression releases but no springs only levers with detents

 

[Stu Jackson]

stu, when i first got the boat i had terrible trouble starting my M25. after all kinds of useless advice i bought an engine manual, sat down and read it, and have not had any starting trouble since. at least 20 seconds of glo plug - right there in the manual.

Very good advice.

My point was he doesn't have to BUY a manual, we have it posted right on our C34 website in the link I provided. Wouldn't hurt to print it out.

 

[mortyd]

thanks stu, but some of us still like things like paper books and sail boats.