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Old 30-04-2013, 17:40   #46
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Re: Yanmar Issues Still

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Originally Posted by travisD View Post
A bit of grayish white smoke on start up could point to a poor injector. The seat between the injector tip and needle can and will wear or the spring is weak. This could allow a small amount of raw fuel to leak into the cylinder as well as air to find its way into the injector. This will give hard starting and the smoke on start up. Like someone already stated. All mechanical/electric governed diesels are at wide open throttle for stat up.
But would a leaky injector cause high crankcase pressure. That's what I'm not sure of. Seems low compression would cause the same thing.
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Old 30-04-2013, 18:06   #47
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Re: Yanmar Issues Still

id have a hard time believing its rings after 1000 hours.. but not a diesel mechanic.. Id lean toward head gasket.. its in the range to service the injectors.. but think the problem is another issue.
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Old 30-04-2013, 18:17   #48
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Re: Yanmar Issues Still

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But would a leaky injector cause high crankcase pressure. That's what I'm not sure of. Seems low compression would cause the same thing.
No it wont cause the high crank case pressure issue . Hard to believe at 1000 hours you are having issues. But if it has idled or ran without enough load for long periods of time the cylinders will get glazed, rings and valves will have lots of build up. This will lead to all the problems you are encountering.Without the heat cause by a good load on the engine bad things happen to diesels.
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Old 30-04-2013, 18:29   #49
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Re: Yanmar Issues Still

I know. I've not run it a lot at idle. I do use it about 300 hours a year and have for a number of years. I always changed the oil and filters when they are due. I can't believe its rings either. Mainly run 2100-2200 RPM. Really the engine is a bit large for my 25' water line.

I'm hoping its a head gasket, blown out at either between cylinders or toward the pushrods.

I was adjusting the valves today and when cranking / bumping the starter I would get a cloud of smoke from the engine. Then the blonde pulled the stop knob so the cylinders would not get fuel. I bump the engine when adjusting valves, mainly because I've a V-drive and am too lazy to clean out the lazzerette to climb below to turn the crank by hand.
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Old 30-04-2013, 18:37   #50
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Re: Yanmar Issues Still

I would go back and check fuel again. Might not be the problem but a whole lot easier to check. 1000 hours doesn't seem like enough for a lot of the suggestions.

I once had a very similar problem that was traced to a hairline split in a fuel hose from a too tight clamp. It wasn't big enough to leak out but would let air in when the engine was off. Starting was extraordinarily hard as the air got cleared from the system but then all was fine. Shutting the engine down for any length of time would let the air in again.

I'd replace the gaskets on the Racor (both handle and top). And what about the secondary filter on the engine? I'd replace it too. Then go over the fuel hose inch by inch looking for any problem.
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Old 30-04-2013, 18:42   #51
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Re: Yanmar Issues Still

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Originally Posted by sailorchic34 View Post
I'm hoping its the head gasket or a bad valve or two. I have a spare head gasket, but sort of waiting till I know if its the head gasket or not.
As you observed further up the thread, if a head gasket fails in the right place, it could lead to crankcase pressurisation as well as low compression

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Originally Posted by sailorchic34 View Post

Glazed bores is a possiblity.
Given the lowish hours, that does seem plausible (I came back to post to that effect). Do you run for extended periods at relatively low loads, eg to charge batteries, or trickling along under power, or motorsailing?
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Old 30-04-2013, 18:55   #52
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Re: Yanmar Issues Still

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As you observed further up the thread, if a head gasket fails in the right place, it could lead to crankcase pressurisation as well as low compression

Given the lowish hours, that does seem plausible (I came back to post to that effect). Do you run for extended periods at relatively low loads, eg to charge batteries, or trickling along under power, or motorsailing?
I don't ever use the engine for charging unless I'm moving. Really other the the 5 minute warm up and warm down I pretty much run the engine at speed. If I'm motorsailing its usually mostly motoring with a jib out. If there is enough wind to move the boat a few knots, I'll sail.

I'm really hoping its the head gasket. It's at least possible. I'm going to pull the head first anyway.

You know I have not changed the secondary filter yet. Though the old racor was a 2 micron. I replaced that with a 10 micron a month ago and no change in starting. I replaced both gaskets on the racor then too

The last time I changed the secondary, the old secondary looked brand new, after 300 hours. I may pull the secondary, but then again it would not cause the high blowby, oil use.
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Old 30-04-2013, 18:56   #53
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Re: Yanmar Issues Still

If the crankcase pressure is high then the compression is bleeding around the rings. If a valve had any issues it would blow back out the intake or leak off to the exhaust. You would not really know the latter unless you where down near the exhaust and listened for the impulses. Leaky injectors can wash down the cylinders. Sounds like border line compression. All though Im in Texas I do know a little bit about diesels. With just a quick Google the compression should be high 300s one spec I found was 412 PSI. That make sense with no glow plugs you have to smash the hell out of the fuel to get it to light.
Note does the motor require valve adjustments? If so you could losing some juice there.
Dont just tear the thing apart, do a compression test. Im sure there is specific tool that will do the job. Do a test dry and then squirt some motor oil down each Cyl. [one at a time] hook up the gauge and retest. If the values go by decent amount then you are diagnosing the problem [leakage around the rings] if its low and does not climb with the oil then the top end could be a issue. All 4 Cyl. should be well into the 300s in my opinion.
What ever you do its going to cost a few bucks you might be able to rent a compression tester for diesels [which will handle the high pressure].
during the test procedure crank the motor until the gauge no longer climbs[increases] read the number and move to the next hole. If your first or second reading is below 300 then I would think it is borderline and ask yourself do you want a unreliable motor. Injectors should be tested at least if you are going to do any major repairs.
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Old 30-04-2013, 19:00   #54
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Re: Yanmar Issues Still

Did this happen suddenly or gradually and getting worse?

If suddenly, I think it would indicate a failure of something, virtually eliminating glazed bores, pitted valves etc. On the other hand, the converse is not necessarily true as something broken could easily become worse.

Other than that I will leave it to the more knowledgeable diesel experts on here to comment.
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Old 30-04-2013, 19:21   #55
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Re: Yanmar Issues Still

I guess this is thread #2 on this? I couldnt find my early post, but as I said then, I had very similar problem in a 3GM30.... was a broken "ring land" on piston on one cylinder. Less than 2500 hours on that engine. The other engine in that catamaran was replaced under warranty (~500 hours) and had similar problems but I never heard what the problem was. Might be that Yanmar had issues with pistons on some of those....?
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Old 30-04-2013, 19:25   #56
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Re: Yanmar Issues Still

Sorry that it is your woe, but this a good stuff. I have always wondered about the Yanmar (freshwater) running so cold. I can see my yanmar heading in the same direction after only 500hrs. IMO, needs a higher set thermostat.
I do know that the diesels I have run the hardest lasted the longest. As long as not >100degsC!
Is it fuming much out the dipstick hole and the rocker cover oil filler, running?
Compression test will reveal all I feel.
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Old 30-04-2013, 20:37   #57
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Re: Yanmar Issues Still

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Originally Posted by Wanderlust View Post
Did this happen suddenly or gradually and getting worse?

If suddenly, I think it would indicate a failure of something, virtually eliminating glazed bores, pitted valves etc. On the other hand, the converse is not necessarily true as something broken could easily become worse.

Other than that I will leave it to the more knowledgeable diesel experts on here to comment.
It happened pretty quick, over last year I guess, effecting two out of three cylinders. Though it seems to be getting worst.
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Old 30-04-2013, 20:47   #58
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Re: Yanmar Issues Still

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Originally Posted by lateral View Post
Sorry that it is your woe, but this a good stuff. I have always wondered about the Yanmar (freshwater) running so cold. I can see my yanmar heading in the same direction after only 500hrs. IMO, needs a higher set thermostat.
I do know that the diesels I have run the hardest lasted the longest. As long as not >100degsC!
Is it fuming much out the dipstick hole and the rocker cover oil filler, running?
Compression test will reveal all I feel.
Its blowing out the crankcase vent to intake manifold. Took off the oil filler cap today and it was blowing a big cloud of smoke. Odd that it does not blow the dipstick. It was leaking around the valve cover bolts at one time. I checked the PCV port on the intake and it might have been plugged. In any event it is Not plugged now. The oil leaking at the valve cover bolts was when I knew the engine had "issues".

My engine always ran at about 170 degrees. Now its near 180 degrees F and warms up in just 2 minutes. Use to take 5-10 minutes to warm up. That makes me think its the head gasket, or hope its the head gasket anyway.
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Old 30-04-2013, 20:53   #59
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Re: Yanmar Issues Still

I know it's a long shot, but I'd go back and look at those racor gaskets - especially the little one on the handle. Maybe it's got a nick or is not seated right. And I'd change the secondary to replace its gasket. Your problem isn't a clogged filter because the engine runs fine after startup. But a tiny air leak somewhere in the fuel system fits the symptoms.

Your initial post said:

"Its hard starting, hot or cold. Acts exactly the same...Once started and running on all cylinders it runs fine"

A lot of the things you're considering just don't fit. The engine wouldn't run "fine".

Remember that there may be several things slightly wrong with the engine but only one is probably causing the hard starting. It can be really confusing.
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Old 30-04-2013, 21:05   #60
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Re: Yanmar Issues Still

The secondary filter is on my list to change tomorrow.
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