Starting to get scared about this engine..#2

n3935j · Sep 25, 2006

I might have missed this fact in a earlier email, but have you checked the compression in both cylinders?
groundhog groundhog1rb@... wrote:

Forgot to mention..brbr

-The boat no longer konks out. Before the boat would labor and stop at some point. brbr

-at about half throttle, the exhaust seems white. above this it gets black.brbr

Thanks for the help,
ghbrbr

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wxt8981 · Sep 25, 2006

I have the feeling at one time or another you've got water
into the engine (back-up from the exhaust line). Check the
compression; that could explain the white and/or black
smoke.
Wilhelm, V-257

rchrdcoe · Sep 25, 2006

Groundhogh
Do you have a combi drive or transmission? I would check the
compression and also look at the timing. There was a discussion of
that(timing) on here a while back. Check it out.
Richard V1812

groundhogyh · Sep 25, 2006

Hello,brbr

I really appreciate your input as I am not a mechanic of any type of engine so I am doing this stuff basically from the information on this forum.brbr

I don't have the combi on this boat.
I did see the detailed discussions on fuel timing in the forum history.brbr

I was hoping we wouldn't be going down the compression road....
But how do you measure the compression on the MD6A? Should I do that before investing my time into the fuel timing?brbr

One other thing. If the compression is bad, does that mean an engine rebuild? And how hard is that?brbr

Thanks,
groundhog
#1813brbr

wxt8981 · Sep 25, 2006

Hi:
Testing the compression is a simple tast- if you have the
tools. Though I recommend doing it (I guess you know a
mechanic who has the tools.) If the compression is low,
that could mean the valves are bad (no worry- it's easy to
grind the valves and have them seated right). But as I
mentioned in my other e-mail, you could have had water in
the cylinders. Then the piston rings could be shut - and a
lot of other things! If that's the case, you have a major
repair! Depending how old the engine is, if fairly new,
repair, but if older, then get a new engine. It's usually
the best thing to do (I did it)
Good luck.... Wilhelm- V-257

rchrdcoe · Sep 26, 2006

-Groundhogh-
I recently had a valve job done on my MD6A. They replaced the springs
and valve seats. The valves were too expensive so reground the old
ones. Total cost was $800. I did the head removal and reassembly my-
self.
Richard V1812-- In AlbinVega@yahoogroups.com, WL wxt8981@... wrote:

groundhogyh · Sep 26, 2006

Is a special type of compression gauge needed or can I find one at the local automotive store? I guess it needs to be put down into the injector holes. What holds the gauge in? Diesel compression is higher, so do I need a diesel gauge?brbr

Once I get it in, I guess I just crank the engine and read it. What type of readings should I see for good compression? Bad compression?brbr

Thanks,
groundhogbrbr