Re-gearing OMC 800

Howard Sterndrive

Rear Admiral
Joined
Nov 5, 2008
Messages
4,603
Re: Re-gearing OMC 800

Howard,

So if I were to purchase that item you messaged me, that would replace all of the safety inefficiencies you found on my pics?
answered here perfectly:
You also need to make sure you have a marine carb, starter, alt, fuel pump, and fuel lines.


Assuming this is a 357, it would be worth rebuilding then?
you lost me there....
why are you rebuilding it?
Does it have low compression or low oil pressure?
 

Crisco87

Cadet
Joined
Apr 27, 2009
Messages
12
Re: Re-gearing OMC 800

So to update...
I have been working on finding a job. I am separating from the Navy so it's a little stressful.

I looked and I do, in fact, have a marine distributor, alternator, carb. The fuel lines are marine but not the recommended A1 (I think). If I remember they are A2 or something similiar.

I am going to do a compression test tomorrow to see where my loss of power is. My buddy and I pulled two of the plugs just to see how they look. They're definitely old. Once I pulled the second plug out he looked at it, laughed and said, "well I think we found your power loss problem." Apparently the previous owner put the plugs in but didn't use the right wires so some of the plugs weren't even igniting. He said he wouldn't be surprised if, when I pull the plugs tomorrow, I pull out two or three more that haven't even ignited once.

So basically my engine has been running on 4-7 cylinders. Nice.

Gotta love used boats.
 

boatguya1

Chief Petty Officer
Joined
Apr 24, 2009
Messages
444
Re: Re-gearing OMC 800

Marine distributor? Maybe I remember the wrong picture, but didin't you post a pic of a distributor that had an ignition module on the cap. I'm not familiar with that marine setup, again maybe I remember the wrong photo or just have not run into the marine dist that looks like it came from a chevy car/truck.

James
 

Howard Sterndrive

Rear Admiral
Joined
Nov 5, 2008
Messages
4,603
Re: Re-gearing OMC 800

Marine distributor? Maybe I remember the wrong picture, but didin't you post a pic of a distributor that had an ignition module on the cap.
yeah, it also had a vacuum advance pot on it. automotive HEI. not marine.
 

Crisco87

Cadet
Joined
Apr 27, 2009
Messages
12
Re: Re-gearing OMC 800

It is an HEI....but I was told that HEI applications are safe in marine because there is no spark. Was my mechanic incorrect?

--- Edit ---

Also, the casting number is, in fact, 3970010. My mechanic was helping my further identify it to make sure it is a 350 and not a late model 305. However, the serial number is all but gone. Does anyone know of a way to identify the engine without the serial number?
 

Howard Sterndrive

Rear Admiral
Joined
Nov 5, 2008
Messages
4,603
Re: Re-gearing OMC 800

I was told that HEI applications are safe in marine because there is no spark. Was my mechanic incorrect?

That's kind of funny, actually.... and yet sad...
The job of the distributor is to distribute spark. There is no spark at the points, as it is pointless ignition .....but there is still 50,000 volt distribution of spark
On a 1 hour run at 2000 rpm, guess how many sparks there are under that cap?









would you believe 480,000 ?
 

Crisco87

Cadet
Joined
Apr 27, 2009
Messages
12
Re: Re-gearing OMC 800

Well my problems just got a lot worse.

I did a compression check and got a range from 90-approx 115/120. I am trying to decide now if it is worth doing a valve job/head gasket or completely rebuilding or just going all out and selling it.

Not fun.
 
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