83 mariner 15 HP cooling system problems

[filthy]

Hi Guys, I have a 15HP mariner 83 model from best i can tell, when cold it starts and runs fine with lots o water coming out the telltale but when it warms up the water flow stops and engine overheats, is this just a blocked thermostat or water passages? Any help would be apreciated.
Thanks in advance.

 

[Maxz695]

Re: 83 mariner 15 HP cooling system problems

When was the impellor changed last? You may have lost fins that are blocking off water flow in the port passages. When cold starting no water pressure in the ports allow flow. When under presure the fins are pushed into the passages blocking flow. Not totally sur if there is a bypass at the thermostat but I would think so. There would still be some flow when the T stat didn,t open (Gone Bad). Just a thought.

 

[Faztbullet]

Re: 83 mariner 15 HP cooling system problems

Sounds like a blocked t-stat, pull the t-stat cover on cylinder head and remove t-stat, stat engine on hose/barrel and rev up to flush passage. Also could be a head gasket leaking an pressurizing cooling system keeping it from cooling...

 

[filthy]

Re: 83 mariner 15 HP cooling system problems

Yeah thanks guys, thermostat is pretty much what i was thinking but hadnt thought of the whole broken vanes thing, just had the motor serviced but when i dragged the boat 3 hours down the road to use it for the weekend it ran for like two minutes then died, just wanted a few 2nd opinions so I could go in and blast the a@#hole that did the service, Ruined my whole weekend! Ah well rant over,
thanks again

 

[filthy]

Re: 83 mariner 15 HP cooling system problems

So, threw it back at the mechanic who serviced it and after pulling the head off it turns out that the passage ways in the head were blocked and he claims that after he serviced the motor it may have dislodged more crap which blocked them completly, Anyways not here to have a rant just wanted to let people know what the end fault was.