Deisel engine Yanmar YSM12 Frozen, 12hp how to free up engine

[David760]

Hello this is a single cylinder engine it was rebuilt in great running condition [so i want to save it] , however i let it sit for years and water came up to about halfway up the engine, for about a year, and I can't move the engine with the hand crank
is there a way to work it free and restart it, ? [like pouring oil in the cylinder] or is it just done?

any advise would be appreciated

 

[DownWest]

Probably a gonner, But, drain the oil and see what it looks like. If it was seawater and there is some in oil, likely your only chance is too strip it.
If nothing inside, pull the injector and look at that, if corroded, get it checked, but before spending money, pour some diesel or plus gas releasing fluid into the cylinder, wait a day and try turning it again, back and forward.
Personally, I would just heave it out and strip it on the bench. More chance of saving it, rather than trying to run it as is.

 

[dansaskip]

Personally, I would just heave it out and strip it on the bench. More chance of saving it, rather than trying to run it as is.

Good advice.

 

[garymalmgren]

40 years ago my YSE 12 rusted solid in Singapore due to my inattention.
I restored it, So it can be done.

RE is there a way to work it free and restart it, ? [like pouring oil in the cylinder] or is it just done?

Yes, but it has to be done properly.

First remove the engine from the boat.
Strip the engine down completely.
Apply de-seizing solutions to the bore above and below the piston. Let stand.
There are a range of home made and ready bought solutions available.
Heat piston and rapidly cool it.
Drive out piston from above or below with a BIG hammer and a suitable lump of wood.
Once you have the engine apart assess, order parts and rebuild.

gary

 

[earlybird]

The Yanmar is basically a very simple engine. The horizontal cylinder has a replaceable wet-liner sealed by O rings so a new one might be obtainable if the old one is beyond redemption. For removal, the engine can probably be part dismantled in the boat to minimise weight lifting.

 

[DinghyMan]

40 years ago my YSE 12 rusted solid in Singapore due to my inattention.
I restored it, So it can be done.

RE is there a way to work it free and restart it, ? [like pouring oil in the cylinder] or is it just done?

Yes, but it has to be done properly.

First remove the engine from the boat.
Strip the engine down completely.
Apply de-seizing solutions to the bore above and below the piston. Let stand.
There are a range of home made and ready bought solutions available.
Heat piston and rapidly cool it.
Drive out piston from above or below with a BIG hammer and a suitable lump of wood.
Once you have the engine apart assess, order parts and rebuild.

gary

Evaporust works well to remove rust in cylinders

 

[Jim@sea]

If you are trying to unseize an engine I was told that you should try and turn the engine backwards so if it has seized you are turning it away from where it is stuck.

(don't do this at home,. I had a two cylinder dumper which would not start so I decided to tow it to start, when I started to tow the driver of the dumper wrongly selected reverse, the engine started and ran backwards, the air intake was belching exhaust fumes and the exhaust was the air intake)

 

[Refueler]

My Perkins 4-99 suffered similar fate ... boat filled with water and engine was about 1/3rd under. We checked oil ... bled system ... pulled injectors and squirted allsorts in ... (diesel mechanic with me) ... short of taking the engine apart we did what we could.
Finally pressed start and she fired up lovely ...

2 weeks later she was seized solid. Mechanic tried - shook head and said choice is replace or a serious strip down and refurb ... yard offered me a scrap 4-107 for 250 quid - a straight drop in replacement ...
Over 20years later the 4-107 is still running sweet.

Basically to OP .... if it was me - lift out - strip it down and make sure she's clean and good to go ... I learnt the hard way.