New to me 25ft with 350 big block and OMC Cobra outdrive!?!?!?!?!

LAC_STS

Master Chief Petty Officer
Joined
Jul 1, 2010
Messages
895
Hi all,

I just bought a 25ft Donzi with a 350 big block and OMC Cobra out drive. The guy I bought it from had his original engine lock up on him, and the outdrive needed an overhaul. So he bought a remanned long block and found a better deal on a refurbed outdrive than the marina he was dealing with wanted to rebuild his.

So I talked to the marina and I have all the receipts from all the work he did to it. The marina said he bought the long block online and had it shipped to them. they re used whatever parts were still good on the old engine. They did use new heads. They dipped the risers and manifolds in acid and re used them. (Never heard of that but thats what they said.)

Like I said I have all the receipts and they have a whole page of parts that they charged him for new.



Couple things Im worried about. There is no thermostat in there. The engine runs at 140 or so unless your WOT. The engine is a PITA to dock and get going because it will act like it wants to stall or will stall when you first put it into gear unless you give it a good bit of gas.

Like when you go from slow to neutral the engine sounds like it is completely dead for 2 seconds then comes back. same thing when you put it into gear and just try to go really slow.

If I throw in a 160 degree t-stat will it help this? I am thinking that the engine is running too cold all the time. Like its not warmed up ever.

Oh yea its a carb engine, not EFI. I am not sure what kind of carb is on there but it looks new. I don't even know how I would go about finding out but I will try.

The other thing is that when I went out with the guy to do a sea trial or test drive or whatever I looked in the bilge and since it had just rained a little bit of water had made its way in there but it was just water. I kept an eye on it and no more came in and it was still just water.

I took it out today (all day) for the first time. It was pouring for about two hours so I left it at the dock and again some water made it into the bilge where the engine is. But this time it had oil in it. A decent amount of oil. I checked the oil on the engine and it is fine on the dipstick.

Any idea of where this oil is coming from?



Thanks so much.
 

Don S

Honorary Moderator Emeritus
Joined
Aug 31, 2004
Messages
62,321
Re: New to me 25ft with 350 big block and OMC Cobra outdrive!?!?!?!?!

A 350 is a small block chevy, not a big block.

Cleaned manifolds and risers are a disaster waiting to happen. They were plugged up or they wouldn't need an acid bath. Replace them now or the engine soon. Your choice.

Yes, you need a thermostat.
 

LAC_STS

Master Chief Petty Officer
Joined
Jul 1, 2010
Messages
895
Re: New to me 25ft with 350 big block and OMC Cobra outdrive!?!?!?!?!

Thats what I thought. But I have saw engines online that say 350 long block, and on the reciept it says "Customer supplied us with brand new long block to install." So I dunno.


I will install the thermostat tom and see how it runs then. I can get the risers pretty cheap too. So Ill see about them. Right now they are pretty cool but so is the whole motor.



Heres a bunch of 350 long block engines:

http://www.perfprotech.com/store/articles/5.7L_longblock_replacement.aspx

http://www.go2marine.com/product.do?no=198502F

http://www.go2marine.com/product.do?no=198502F

http://www.go2marine.com/product.do?no=156150F

http://www.go2marine.com/product.do?no=155899F
 

Matt89GT

Seaman Apprentice
Joined
Mar 17, 2010
Messages
46
Re: New to me 25ft with 350 big block and OMC Cobra outdrive!?!?!?!?!

Hi all,

I just bought a 25ft Donzi with a 350 big block and OMC Cobra out drive.
What Don is saying is, a 350 is a small block not a big block, A long block is a engine that comes with heads, a short block is a engine with just a rotating assembly with NO HEADS
 

LAC_STS

Master Chief Petty Officer
Joined
Jul 1, 2010
Messages
895
Re: New to me 25ft with 350 big block and OMC Cobra outdrive!?!?!?!?!

Ohhh I see.

So anyone have any idea where the oil is coming from? I tried looking around the engine itself but didn't see it coming from anywhere. Somewhere I should look?



Thanks
 

Matt89GT

Seaman Apprentice
Joined
Mar 17, 2010
Messages
46
Re: New to me 25ft with 350 big block and OMC Cobra outdrive!?!?!?!?!

Well you have options.......if your oil level is fine maybe its not engine oil at all could be a couple things, leaking trim pump, power steering?? I would explore all avenues.
 

LAC_STS

Master Chief Petty Officer
Joined
Jul 1, 2010
Messages
895
Re: New to me 25ft with 350 big block and OMC Cobra outdrive!?!?!?!?!

Well I have an update.

I made another thread because I had took the boat out Friday and Sat and Sat when I was coming back to the dock I noticed the oil pressure was low so I put it in N real quick and it died.

When I checked the oil it was low but I only had to add a quart to get it to where it should be.

But after that the engine would not start. It was about 200 on the temp gauge. It had heated up because it was shut off straight from running it about 3/4 throttle.

After 20 mins or so it started. But it had a tapping sound. I drove it the 1 mile or so back to the dock as slow as I could. I had my friend who is a mech come look at it the next day.

He checked a bunch of stuff and said it is def not a lifter or anything like that. He showed me where you can see where the cam or something (forget what he called it) might be bent. On the big pulley at the bottom you can kind of see it wobble.

He said it might be a rod or a bearing. He said that the oil level was good. I hadn't ran it since the day before when I got it back to the dock. He said that if I only put 1 qt in it and its at a good level now then it was only 1 qt short and that shouldn't have hurt it.

So I got all the oil out of the bilge and put some of those white oil absorbing sheets down and I ran it for a couple mins and I found out that the power steering is leaking and there is oil leaking from what appears to be the rear seal.

My friend is really busy working so I'm trying to figure out as much as I can myself.
 
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