please help. boat overheated. need advice
 

Hello and thanks for looking. I have a four Winns liberator. It has a 260 HP 350. It overheated today on the lake. Was smoking quite a bit. I let it cool down and babied it to the dock. Boat began running very weak all of a sudden which is how I discover the overheating. I could hear water boiling in the exhaust. After cooling boat started and made it back to dock. But with no power. Wouldn't even plain off. I checked the oil for water and there is no water in it . any help appreciated thank you.

The 'lucky' minimum by your description is head gaskets. Do a compression test. 4/6 and or 3/5 are prob leaking combustion into each other.

totally agree with this comment by SB

If that engine got that hot to start smoking-- not good at all.

you may want to look in the bilge and see if there is any substantial water -- cracked the block, manifold etc.

I wish you all the best


3pointstar

And I would not re use the risers and the exhaust manifolds on a repower / rebuild. This most likely is close to a 27 to 30 year app having a Mercruiser in it. Also IF APPLICABLE - the exhaust Y pipe will need to be check out very closely and 4 sure change the heart shape O ring gasket at the bottom flange to the inner transom assembly. So many people miss that one after a hard overheat doing the repower / rebuild . Just saying. IMO I think the motor is hurt internally in some shape or form like others have posted

Thank you guys. I will be doing a compression test tomorrow. The motor was already tired before only having 100lbs per cylinder. I'll post tomorrow let ya know what I come up with. Anyone off hand know the firing order? Its a 1986.

1-8-4-3-6-5-7-2

Every guy should know those numbers more than their own b-day, right behind Jenny's number. :)

Agreed!! FYI, BB Chevy's have same firing order.
Good luck with the diagnosis, as you probably know, this place is a wealth of knowledge and "entertainment".

OK here is the test real quick what is a marine GM base small block with reverse rotation firing order ? there is a very simple simple way to remember this if you do not know it but know the standard firing order.

Reverse firing order is 8-6-7-5-3-0-9.

Sounds like you have a great opportunity to upgrade to a 383... btw unless youre hung like john holmes its hard to pick up hot chicks with only 260hp.... just my .02...rm