1973 Sportwin running hot

L

loco50

Seaman Apprentice
Joined
Jan 5, 2012
Messages
37
I replaced the water pump on a 9.5 Sportwin. I had never cranked this motor up before as I just purchased it. As soon as it cranked up it spit water out of the water outlet port fairly strongly. I let it run for several minutes and when I noticed the water coming out started turning to steam. Is this a bad thermostate issue or is it a head gasket issue.
 
Joe Reeves

Joe Reeves

Supreme Mariner
Joined
Feb 24, 2002
Messages
13,262
Re: 1973 Sportwin running hot

Hard to tell really without actually being there, but it's a good idea to replace the thermostat if its condition is unknown when replacing the water pump.

If a head gasket were bad, you would have a difference in compression... also there should be traces of water on the spark plug(s).

If you were running the engine in a barrel, trash can, etc (you didn't say), the water level must be a few inches above the water pump as the pump is not a self priming item. If lower than the pump or around the same level, having the pump suddenly develop a air pocket is a good possibility.
 
L

loco50

Seaman Apprentice
Joined
Jan 5, 2012
Messages
37
Re: 1973 Sportwin running hot

Was running in a barrel and the water level was high. Too high really. But since i put a new water pump in I wanted to not take any chances. I just thought it odd that it would spit a strong stream cold. Maybe the thermostate is no good.
 
kbait

kbait

Commander
Joined
Nov 13, 2007
Messages
2,449
Re: 1973 Sportwin running hot

Should be able to grasp the spark plug bases for several seconds when warmed up in the barrel on high idle. Then try the slowest idle and see if it heats up more. if it starts steaming and heating up, it's not pumping correctly. If it feels cool, check out thermostat.. some folks remove 'em entirely but it needs to be there and functional for the motor to run optimally @ proper running temp.
 
L

loco50

Seaman Apprentice
Joined
Jan 5, 2012
Messages
37
Re: 1973 Sportwin running hot

I replaced thermostat(there was none) I also pulled the head and it was warped. Had it machined flat again and replaced head gasket. When I cranked the motor up it basically did the same thing. Spits water fine, then starts to head up and run hot again. I am stumped.
 
You must log in or register to reply here.
Top