Yanmar 1gm10 Engine Failure

[sailor Martin]

hello,

i have a 1gm10 yanmar engine (one cilynder) on my 29 feet sailboat.
yesterday night we had some rough weather while sailing. i hed to do a small engine manuver to solv a problam with the rig. the starter didnt work so i had to use the manual starting. it is usually a phisical effort but im used to it now. but this time it took me 3 tryels and it was especially hard. finally it started with a very strange rithem of work. after 5 seconds it made a big boom! ternd off and exheld a lot of smoke from the air inlet. i didnt try to start it agein after that untill we arrived in the marina today.

today i started it agein menually (took a few tryls) and it made the strange rithem agein so i ternd it off fast after 3 seconds. i made some priming to the fule sistem and tryd agein to start it and it workd fine.

i checkd the air filter becouse of the smoke that came out of the air inlet and found a lot of soot with an oily texture when you toch the filter. i checkd the engine oil level and its full. what is the meaning of the smoke exiting the air inlet? or the big boom that coused the smoke? im worride aboute some dammage to the cilynder. or maybe something else? anybody know the meaning of this?

i should say that my engine is an old one with up to 28 years behinde him. i made 350 hours on it in the last year myself but i have been making all the oil and filter maintenence on time. i even made valve clearence 250 hours ago (3 mounth ago).

thanks a lot

[model 10]

How about a stuck intake valve? Or how about some water got into the cylinder? With just 1 cylinder it should be easy to narrow it down

[dynamo]

I have read somewhere they can fire/run backwards if hand starting.

[Cheechako]

Yeah, could be a bad failure or simple. Maybe it did get water in the cylinder from the rough weather? Maybe that would damage a valve....need to logic that out.... Could just be a coincidence and a piston has failed...

[dynamo]

See thread: Yanmar 1gm10 starting in reverse!!

[bsurvey]

take an oil sample for spectro analysis it may tell you whats going on.

it measure trace metals and water if any in ppm and usually will detect any issues before they go catastrophic

its about 25 dollars for the test and the trun around should be 24 hrs or less

[Sea7King]

So, where do you get the oil test done?

[bsurvey]

looks like you are in stuart Fla?

I am in California

Company Called SGS may have a subsidiary in you location that does oil analysis called spectro analysis. you just want trace metals wear in ppm and look for water

you can try googling it spectro analysis stuart fla. you can call any full service boat yard or big diesel repair or service location and ask who they may use locally
marine surveyors in your area may also know who is local
the container has to be really clean, and the sample can be less than or equal to half of a baby food jar, glass plastic doesn't matter just has to be really clean. they will be looking at PPM's so any trace of any type of contaminant will show up in the sample.

use a new piece of hose preferably clear and suck it out of the dip stick.

don't take samples from the bottom of the oil pan or from the oil filter too much sludge hope that helps

[model 10]

Originally Posted by Sea7King

So, where do you get the oil test done?

It will be a total waste of money. Oil test are for trends, not for an engine blowing up.

[d design]

Your engine was running backward. This happens when the engine bounces backwards off the first combustion and starts working in reverse by sucking air in through the exhaust and blowing out the intake(hence the sooty air intake). You are lucky your engine didn't suck in water, hydro-lock and throw a rod or worse.

[Cheechako]

Originally Posted by Guy

It will be a total waste of money. Oil test are for trends, not for an engine blowing up.

That's what I've heard also. Although... maybe it would show if there is a high level of AF in the oil? Don't need a trend to know that's not right!

[a64pilot]

Years ago Harley Davidson made a two cylinder horizontally opposed two stroke golf cart. Had two sets of points and a starter generator, when you wanted to go in reverse you stopped and flipped a switch, this switch changed to the other set of points and the starter spun backwards, motor ran just fine running backwards

[bsurvey]

I am afraid our friend GUY is wrong. in deed oil analysis will detect trends. it will also tell you in one shot whether there is salt water in the oil ie a blown head gasket and will show you levels of engine internal material above the normal range. as the laboratory will point it out to you. AF will also show up immediately

it is the cheapest form of trouble shooting. unless you want to start taking apoart your engine

don't think 25 bucks is a waste of money considering the alternatives

I have only been using oil analysis for 35 years and am quit skilled this point in how to apply the information

[model 10]

Originally Posted by bsurvey

I am afraid our friend GUY is wrong. in deed oil analysis will detect trends. it will also tell you in one shot whether there is salt water in the oil ie a blown head gasket and will show you levels of engine internal material above the normal range. as the laboratory will point it out to you. AF will also show up immediately

it is the cheapest form of trouble shooting. unless you want to start taking apoart your engine

don't think 25 bucks is a waste of money considering the alternatives

I have only been using oil analysis for 35 years and am quit skilled this point in how to apply the information

Before most professional mechanics waste $25 on an oil test for an engine that you think has blown up, you might look for water or AF in the oil or metal parts in the oil pan or filter. or even a compression test. In the space of time that it takes for an engine to self destruct you are not going to get anything in the oil that a spectro anaylisis it going to pick up. This is kind of why it's a trend anylisis, It picks up on things tiny things as your engine wears out not when it blows up. Not to mention it takes days to get your info back.
I to have been doing oil samples for 35 years and I would never try to sell someone on this for a one time test. If you read the directions that come with a sample kit, they will even tell you that.