Engine still cuts out!

[roy]

Hi all,
I have been having problems with my MD6A. I can't seem to throttle up to full power. I purchased this boat in May and I have yet to see this boat go full speed. The symptoms and things done so far are listed below.brbr

1.) I noticed that if I throttled up, the engine would cut out. Like as if it was running out of gas. Wait a few minutes and you can start it again. Keep the throttle very low and you can run the engine without problem.brbr

2.) One day, the engine would not start. It would turn over for about 3-5 seconds and cut out.brbr

3.) I replaced and/or cleaned all associated filters. Replaced electric fuel pump. I could run engine, in neutral, at full throttle for a long time.br
I bled the system as it describes in the motor manual. You open the little screw on top of the fine fuel filter fixture.brbr

4.) When the boat was taken out, with the engine in loaded conditions (motor doing work), I started with low throttle. Fine..br
Then I would increase throttle little by little. At about 1/2 throttle point and above, I noticed that the RPMs would not go any higher. br
The engine would eventually cut out again, with the same ability to start up again after a few minutes. And the same thing where you can run it for a long time at low throttle.brbr

The exhaust gas seems darker now compared to before I did this work on the engine (as I am new to this, I don't know what the exhaust is supposed to look like). Right when I start up the engine, there is a black discharge out the exhaust. brbr

Could I still have air in the line?br
Should I have bled the system all the way at the top where the fuel injectors are?br
If I just open the lever that decompresses the cylinders and turn over the motor for awhile, is that bleeding the system of air?br
Could my main, mechanical fuel pump be bad?brbr

Thanks for any input,br
groundhog
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[chris20636]

Groundhog:

Your problem sounds very much like the one I had with my MD6-A a couple
years ago. I fought it and paid over $2,000, a little at a time, for help.

I solved the problem myself by doing the only thing I hadn't done before: I
removed the head and had it cleaned and the valves ground - yes, even though
it had decent compression before removing it. Total cost for this was about
$65.00. New gasket set (including head gasket) was another $85.00, as I
recall.

While the head was at the shop, I cleaned the tops of the pistons and
rodded out the water passages.

Removing and replacing the head was not a tremendous job. Be sure to follow
the directions and head-bolt tightening order.

Where are you? Contact me out-of-group (_saylered@..._
(mailto:saylered@...) ) and I will try to answer any questions.

Ed Davis

 

[trevy_kins]

Groundhog, have you checked the diaphragm in your mechanical fuel pump?
Trevor V2915

________________________________

From: AlbinVega@yahoogroups.com [mailto:AlbinVega@yahoogroups.com] On
Behalf Of SaylerEd@...
Sent: September 5, 2006 10:43 AM
To: AlbinVega@yahoogroups.com
Subject: Re: [AlbinVega] Engine still cuts out!
Groundhog:

Your problem sounds very much like the one I had with my MD6-A a couple
years ago. I fought it and paid over $2,000, a little at a time, for
help.

I solved the problem myself by doing the only thing I hadn't done
before: I
removed the head and had it cleaned and the valves ground - yes, even
though
it had decent compression before removing it. Total cost for this was
about
$65.00. New gasket set (including head gasket) was another $85.00, as I
recall.

While the head was at the shop, I cleaned the tops of the pistons and
rodded out the water passages.

Removing and replacing the head was not a tremendous job. Be sure to
follow
the directions and head-bolt tightening order.

Where are you? Contact me out-of-group (_saylered@...
mailto:_saylered%40aol.com _
(mailto:saylered@... mailto:saylered%40aol.com ) ) and I will try
to answer any questions.

Ed Davis