My New Old ($300.00 Bargain???) boat.

[swampboy]

This last June I purchased a 1966 Gulf Stream 17 footer. Mercruiser 120 outdrive. I installed a new impeller in the lower unit. I rebuilt a badly rusted carb..I pulled the head and found that # 4 cyl has rust that prevented the piston from moving thru complete turn. The # 2 cyl has some rust,but not as bad as the # 4. I pulled the complete outdrive and then pulled the motor. The bottom looked clean and had some oil and trans fluid that I had poured in to the cyls. There were some fragments of metal that come off the oil pump and were in the pan.. The head is coated with a thick coat of carbon. Now what do I do?? I have a machine shop close by in Fresno, Ca.That I have used in the past for machine work on my 72 Nova and 67 Chevelle . I installed the engine parts and everything went well. I can have the machine shop check-out everything and either give me some good or bad news...I understand that the 120 is the same motor that was used in the Chev II's. Is this correct???Anyone had a similar problem??What did you do?? What was the final results and cost Thanks for your help.

 

[elkhunter338]

Re: My New Old ($300.00 Bargain???) boat.

I would say depends on if you have a good engine block or not. Has the engine block been in salt water and looks like there is lots of rust and metal missing around the cylinders.
Has it already been bored .030 over? I would not push it to .060 in a boat engine gets those cylinder walls thin.
My 1971 140 in my 1984 boat (did not know that when I bought the boat), broke the timing gear 2 yrs ago. I tore the engine down and found it was punched 0.30, looked like a pin hole was starting to form in the cylinders, and I had water go into the engine when the timing gear broke because the boat come to a sudden stop, I cranked on the engine and hydraliced the cylinders so I might have bent the connecting rods (not sure). with the engine block in poor shape I opt for a brand new engine from michigan motorz.
They are now selling these for $2,000 plus shipping and the pre 90's will need a 12.75 flywheel, new engine coupler, and highly recommend new dist ($100).
Total cost is around $2500 for a brand new engine, you reuse your carb and manifold and will need a special metal gasket to use your old manifold because the new 3.0 use a smaller ports on the head.
I have 140 hrs on my new 3.0. I would have more put in 2008 I lost my outdrive and did not replace it until spring of 2009 with a new sei 106.

I priced rebulding the engine with machine labor and parts and I was going to be in it for quite a bit so I went with a new engine. I also new I was going to plan on running the boat probably 1,000+ hrs in the next 10 yrs.

 

[swampboy]

Re: My New Old ($300.00 Bargain???) boat.

Thanks for the quick reply. Accorging to Prev Owner, the boat was not used in salt water. As far as previous rebuild I dont know, but the rods have a light brown paint mark on them?? Don't know if this means anything. Any way I will have it checked out by Mach shop. At this point I will just wait and see what it may look like for rebuild or ??.I've been looking on the internet for engines and have found some of the same info you have. The rest of the boat needs some tramsom work and the rest is TLC. So far I'm enjoying "My First New Old Boat" I have the time (74 yrs young and retired). I dont have deep pockets, but I can do most of the work myself. Thanks for your help. Great Forum..

 

[Fordiesel69]

Re: My New Old ($300.00 Bargain???) boat.

Check the manifold and exhaust elbow for water entry into the cylinders. If the engine is not cracked, simply bore it 0.10 to 0.30 over and be done with it. I am not a fan of big boring without sleeving it. Especially with the high rpm sustained.

You will have a nice boat when done.

 

[swampboy]

Re: My New Old ($300.00 Bargain???) boat.

Thanks for the input. The carb was rusted and there was rust inside the intake manifold. It looks like it was caused by "Rain". Hopefully the block will be ok for boring. Now it is up to the machine shop to check it out. Then we will go from there. Thanks