200hp Mercury Outboard will overheat at 1800 to 2000 rpm

rlorenc24

Recruit
Joined
Aug 18, 2013
Messages
2
I have a 200hp Mercury outboard 1996 with 75 hours on it,It was in storage for some time. I used it three or four times and noticed the temp going up at a sustained rpm between 1800 and 2000rpm and if continued to run at this rpm it overheated. I had a new water pump and poppet installed. Since then I used it and it seems to have the same problem. It runs normal temp at idle and WOT. My question will concern the poppet valve, someone told me to cut one coil off of the poppet spring to lessen the water pressure that the valve will open and that this a dealer fix. Has anyone had a problem like this or has had this repair done?
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
27,036
Re: 200hp Mercury Outboard will overheat at 1800 to 2000 rpm

Never heard of that "repair". Did you change out the thermostats? When they did the waterpump, did they use new gaskets and wearplate?
 

rlorenc24

Recruit
Joined
Aug 18, 2013
Messages
2
Re: 200hp Mercury Outboard will overheat at 1800 to 2000 rpm

Never heard of that "repair". Did you change out the thermostats? When they did the waterpump, did they use new gaskets and wearplate?

Thermostats, complete waterpump with new gaskets were all rplaced new. The poppet diaphragm and gaskets were replaced, but I don't think the valve and spring were as I didn't get them with the rest of the old parts.
 

Dukedog

Captain
Joined
Oct 6, 2009
Messages
3,235
Re: 200hp Mercury Outboard will overheat at 1800 to 2000 rpm

Sounds like its openin' a little to soon. Some springs will "lose" tension over time. May not be your problem but.....Cuttin' tha spring is a "bs" deal on production motors............
 
Last edited:
Top