how to know if all cilinders is firing

[bolo78910]

hello again guys,

what test t o do to find out if one or more of my cilinder is not firing.

because it seems i just caunt go over 4000 rpm but the endine runs great.

i even drop down to a smaller prop i5 pitch i run a 21 pitch did not make a diffrent, iam now running a 17 pitch ss at 4000 rpm i get 30 miles per hour gps.

also the boat is in the water from early season so i know barniccles is on the hull.

1990 searay 220 da merc 5.7L .


just want to know how to make sure all cilinders is firing>

this is how i know how to do it,

pull one spark plug wire one at a time with engine running, if one plug did not make the engine miss or make a change that cilinder is not firing.

thanks guys just want to get things right for next season.

 

[Gary H NC]

Re: how to know if all cilinders is firing

How long has it been since a complete tune up?
Plugs,wires,cap,rotor and timing set?
Compression test? Clean the hull...a dirty hull can make a huge difference!

 

[Don S]

Re: how to know if all cilinders is firing

pull one spark plug wire one at a time with engine running, if one plug did not make the engine miss or make a change that cilinder is not firing.

That's how you do it.
But it sounds like the problem is the dirty bottom.
A restricted fuel system will also prevent max rpms.
Try this.

http://www.iboats.com/bbboard/bbBoard.cgi?a=viewthread;fid=24;gtid=1107009

 

[bolo78910]

Re: how to know if all cilinders is firing

thanks much guys .

i will try doing the test you linked don s .

bottom is mostly dirty boat is in the water from april.

and living in the northeast this year the barnacles was so bad some guys has to haul there boat to clean off the outdrive because the water passage was clogs with barnacles.

i fish almost every day so i gess moving the boat very often realy help a lot.

thanks again i will post my finds.

 

[Bondo]

Re: how to know if all cilinders is firing

also the boat is in the water from early season so i know barniccles is on the hull.

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