Help find part number of OMC engine

s_explore

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Hello, I have bought myself a Cierra Sunray 1987 boat.

I am restoring completely and other night was looking for a part number n my engine but I didn't find one.

It's a V8 5.0L OMC, I would guess this is a cobra but I am not sure 100%. I need the part number to order some part for it.

Please help me
 

Bondo

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Hello, I have bought myself a Cierra Sunray 1987 boat.

I am restoring completely and other night was looking for a part number n my engine but I didn't find one.

It's a V8 5.0L OMC, I would guess this is a cobra but I am not sure 100%. I need the part number to order some part for it.

Please help me
Ayuh,..... Welcome Aboard,....... What sorta part number,..??

If a 305 Chevy, Cobra drive,.....
From lookin' at the pictures, yer lookin' at 'bout $10, grand before ya go for a boat ride,......
 

s_explore

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Ayuh,..... Welcome Aboard,....... What sorta part number,..??

If a 305 Chevy, Cobra drive,.....
From lookin' at the pictures, yer lookin' at 'bout $10, grand before ya go for a boat ride,......
Why do you say the engine will need 10 grand?
 

Lou C

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Ok what part(s) do you need, many of them are the same for all years of Cobra production but some are not. OMC identified their products by model # which was for the whole power package (engine transom mount and outdrive) this model # is what you use to buy parts. In addition the drive has a serial # on it as well.
the model # were on a sticker that could be on the thermostat housing or the valve cover. If that’s gone best thing to do is find a listing of OMC model #s for your year and use ones that match what you have.
For example:
50= 5 liter
2= 2bbl carb
P= power steering
The letters after these signify the modifications that may have happened along the way. They also use R for right hand prop rotation and L for left hand rotation (counter rotation). Since you have it all torn apart might think about selling off the OMC stuff and converting it to Merc for ease of repair….
 

s_explore

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Ayuh,..... Not the motor, the whole package,......
Oh yeah well I already replace stringers, transom, bulkhead. Project almost finish just need to replace some part on the engine and thats it. Been almost 1year I'm working on it, way more work than i tough. Still it's my first one thats a hell of a job for one man
 

s_explore

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Exhaust gasket, boot exhaust, gimbal gasket. Probably gimbal bearing. I think I should change all gasket, but I need to check compression of the cylinder see if engine is still fine. I think in general engine is healthy but i dont know i need to do some research on how to check an engine
 

Lou C

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The gasket between the pivot housing and the outdrive is the same for all dog clutch Cobra drives as is the gimble bearing. The exhaust gasket do you mean between the cyl head and the engine, or between the manifold and the exhaust elbow? You have the log style manifolds so that's how to identify those parts. The rubber exhaust hoses, same thing you buy based on the exhaust style.
based on the fact that you have an '87 5.0 with a Rochester 4bbl and I'm assuming power steering yours is probably one of these:
In any case the parts for the V8s from 86 to when they changed to the center riser exhaust would likely all be the same. There are aftermarket equivalents out there too you just have to look. And as I said the gasket for the drive to the pivot mount joint and gimble bearing is the same.
 

s_explore

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The gasket between the pivot housing and the outdrive is the same for all dog clutch Cobra drives as is the gimble bearing. The exhaust gasket do you mean between the cyl head and the engine, or between the manifold and the exhaust elbow? You have the log style manifolds so that's how to identify those parts. The rubber exhaust hoses, same thing you buy based on the exhaust style.
based on the fact that you have an '87 5.0 with a Rochester 4bbl and I'm assuming power steering yours is probably one of these:
In any case the parts for the V8s from 86 to when they changed to the center riser exhaust would likely all be the same. There are aftermarket equivalents out there too you just have to look. And as I said the gasket for the drive to the pivot mount joint and gimble bearing is the same.
Thanks a lot that really help me.

Much appreciated. For the gasket I mean the gasket between manifold and exhaust elbow. I didn't check it yet but pretty sure it's gone.

Also the some of the exhaust made in cast iron are rusted and were cover by the last owner with some paste that I don't know what is it. Do you think there is a problem with that or should I check to get me new exhaust?
1634562680234.png
 

Lou C

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That looks like it needs to be taken apart and inspected. If its all rusted up and patched you need to replace it. The gaskets for between the manifold and elbows are still available from BRP, or in the aftermarket (Barr Marine is a good brand). When you take the manifold off the engine you'll be able to see if that was leaking water back in the engine, if so you'll probably have to do a valve job.
 

s_explore

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That looks like it needs to be taken apart and inspected. If its all rusted up and patched you need to replace it. The gaskets for between the manifold and elbows are still available from BRP, or in the aftermarket (Barr Marine is a good brand). When you take the manifold off the engine you'll be able to see if that was leaking water back in the engine, if so you'll probably have to do a valve job.
Oh ok more work than I thought. Thank you again very good info
 

Lou C

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Oh ok more work than I thought. Thank you again very good info
it's ALWAYS more work than we thought! Leaky exhaust on an inboard engine with water cooled manifolds is the #1 killer of engines.
 

s_explore

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it's ALWAYS more work than we thought! Leaky exhaust on an inboard engine with water cooled manifolds is the #1 killer of engines.
Yeah I have noticed that there is seem to be water mixed with oil in those boots of the gimbal housing
1634570922197.png
I am guessing there is some problem with some gasket or something else. I mean I don't know much about engine but I don't think this is normal
 

Lou C

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#76 is the driveshaft bellows, this is supposed to be water tight, no water inside.
#31 is the exhaust bellows this normally has water in it.
 
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