2004 merc 50 bigfoot cooling

[rustysch88]

Hi everyone, im purchasing a lightly used 2004 mercury 50 hp bigfoot.. the issue is that it will get hot after running for a little while. the result is that once it gets hot it wont allow you to go full throttle. i dont know much about this engine as i said im going to be buying it.. im curious of the issues i could run in to. i figure impeller but it has really good flow coming out of the water hole.. ive heard something about a seal that requires the powerhead to be removed? also the issue with not going full throttle, is there a safety built into this engine to cut the power back?

Im getting the engine with all controls and tach, has a vengence stainless prop. all for $1250. is that a good deal in its current condition?

Im planning on putting it on a 1999 g3 1544 aluminum boat. its 15.5' and beam is 66" and converting to remote steering.. I would appreciate all input on everything from the cooling issues to your thoughts on this motor and how it will work on the aluminum boat..

 

[rustysch88]

Re: 2004 merc 50 bigfoot cooling

oh and by lightly used, it only has 60hrs on it.

 

[Silvertip]

Re: 2004 merc 50 bigfoot cooling

1) How do you know it has only 60 hours on it?
2) Why is it being sold with an overheat problem?
3) SIMPLE overheating at idle is caused by a thermostat stuck closed, a bad water pump, or clogged cooling system.
4) SIMPLE overheating at speed is caused by a bypass valve that is stuck shut, a bad water pump or clogged cooling system.
5) SERIOUS overheating problems are due to lean carburetion, lack of lubrication due to low oil, no oil, a bad oil injection system.
6) What I'm trying to point out here is that you are risking "getting lucky" with having a $1250 headache that in the end costs you more than a properly running motor would have.
7) Doesn't matter if this is a two or four stroke motor. If it is a four stroke and the engine is already damaged, you are looking at potentially really expensive repairs.
Unless you know WHY this engine is overheating, you are buying a pig in a poke. As a minimum a scope check of the cylinder bores and a compression check are required.
Almost forgot -- a good tell tale stream does not by any means indicate a good water pump. All it says is that it is pumping SOME water but maybe not enough to cool the engine.

 

[rustysch88]

Re: 2004 merc 50 bigfoot cooling

it is the 4 stroke.. and yes, i am still in a toss up on buying it.. its on their boat right now and runs fine but as said has the cooling issue.. they took it to bass pro shop and were told it would be the seal under the powerhead.. at a $700 to repair.. now thats fine if it really is that.. they are repowering and going to a larger motor..