one hot head and 1 cool head

dieselcat

Petty Officer 1st Class
Joined
Feb 1, 2009
Messages
351
I have a 1987 88 spl rude and 1 of the heads where getting warmer than the other,so 1 day i took the hose off the side that was getting hot and it cooled down in seconds.So i ordered a tstat kit and installed it.started the motor ran it and now it gets hotter than before?would it make a difference if it's on a hose or in the water?I double and triple checked to make sure everything went in as it is suppose to.
 

Mas

Lieutenant Commander
Joined
Oct 3, 2006
Messages
1,656
Re: one hot head and 1 cool head

It is best to check temp out on the water where you'll be using the motor. This will ensure that the water pump is properly submerged.

When you say hot...how hot? Can you leave your hand on the head for a three count?

MAS
 

tashasdaddy

Honorary Moderator Emeritus
Joined
Nov 11, 2005
Messages
51,019
Re: one hot head and 1 cool head

they are known to run hotter on one side than the other, by a few degrees. i do not remember if those have the rubber diverters in them or not. it has been a few years since i have had an 88 spl. you could try back flushing from the tstat. also do a compression check to make sure you don't have a leak into the cooling system.
 

emdsapmgr

Supreme Mariner
Joined
Dec 9, 2005
Messages
11,551
Re: one hot head and 1 cool head

The valve body in the thermostat housing has either one or two pinholes in it, depending on year. If it has two holes and if one plugs up with debris, (a common problem) it will oveheat at idle on that side.
 

dieselcat

Petty Officer 1st Class
Joined
Feb 1, 2009
Messages
351
Re: one hot head and 1 cool head

Cleaned everything thoroughly when i took it apart.before i changed the t-stats 1 side would barely even get warm at idle and the other about twice as hot,if i took the hose off the side that was hot it would cool in a matter of seconds,so i assumed the t-stat was bad on that side.I bought a whole kit and replace them both,started the motor on muffs and both sides got hotter than before.The side that got hot first time before replacing t-stat i could not hold my hand on for more than 6 seconds.
Took the boat on river yesterday ran it for a while took the hood off and everything felt fine,guess the muffs had something to do with it?or maybe it just needed opened up,don't know but seems fine now,but i will defenitly keep an eye on it.
 
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