5.0 riser and outdrive serial numbers

[83vert]

Today I separated one riser from the manifold to see if they needed to be replaced. What do you guys think(it was hard to get a good pic)?

The pics make them look worse than they are, I thought they looked ok. How hard would it be to convert to a closed cooling system? If anybody can tell me what outdrive I have from these serial numbers I would appreciate it. Transom assembly- ob944576
drive unit- ob979193
thanks again guys for all of your help

 

[Don S]

Re: 5.0 riser and outdrive serial numbers

Get the gasket surfaces of the manifolds and risers cleaned up and inspected. My first impression from seeing that one section with the gasket off the surface in picture #2 is that you need new manifolds and risers.

You seem to have mega corrosion, all over the engine.

 

[83vert]

Re: 5.0 riser and outdrive serial numbers

Its not corrosion, it is from the P/O using a fire extinguisher to put out a burning exhaust coupler. I am going through all of the things that may have made the boat overheat. I still need to pull the lower unit but want to find out what unit it is so I can get the right manual.

 

[83vert]

Re: 5.0 riser and outdrive serial numbers

Are these any better????

The last pic you can tell there should be no reason that water can not flow through these. I am not sure what they are supposed to look like.

 

[Don S]

Re: 5.0 riser and outdrive serial numbers

Those look fine from here.
Plugged passages don't appear to be a problem.

What did the rubber hoses that went between the riser and the Y pipe that attaches to the transom shield look like. Were they burned up inside, all crispy?

 

[83vert]

Re: 5.0 riser and outdrive serial numbers

yea the rubber exhaust couplers are definetly in need of replacement. I think the p/o replaced the manifolds and risers not to long before I got the boat but he left it in the water and never ran fresh water through it. Why do the gaskets cover some of the water passages?

 

[Don S]

Re: 5.0 riser and outdrive serial numbers

The FIRST thing you should have checked for the overheat problem is the impeller. They should be replaced every other year as a rule of thumb, if you want to go longer, fine, but you get to worry from the 3rd season on.
Assuming the engine is original, the drive is an Alpha I and is an 88 model, along with the transom shield. Would assume the engine to be also.
Manuals #9 for the engine and #6 for the drive from the Adults only sticky manual link, should set you up with everythiing you need.

 

[Fun Times]

Re: 5.0 riser and outdrive serial numbers

Here is your engine history.

ENG: 0B901625 450S100AS 1988 MERCRUISER 5.0L ALPHA
DRV: 0B979193 5010165AS MERCRUISER ALPHA 1.65:1
Warranty Period: 10/12/1989 - 10/12/1990
Product Protection Period: NONE
Manufacture Date: 10/30/1987
Date Type Dealer Information Misc. Information
10/12/1989 REGISTERED EXP : 10/12/1990
11/03/1987 INVOICED.

For the engine service manual you need # 9
And for the drive service manual you need # 6 R/MR/ALPHA ONE

 

[83vert]

Re: 5.0 riser and outdrive serial numbers

Thanks guys, that was the info I was looking for. Now onto the lower unit.