1990 Mercury 150XR4 getting kinda hot

[jrocksho]

I have a 1990 Mercury 150XR4. Noticed temp gets to about 3/4 mark or higher while running. Can idle all day at normal temps, but when I start running temp slowly rises. No alarm yet, but seems to get hotter the faster I go, then back to normal at idle. I change my pump every year and a half or so, replaced all poppet parts and stats 4-5 years ago, replaced cylinder head gaskets last year. Also water seems warmer than normal coming from telltale. I am thinking stats and poppet, or restriction. I just don't know how to check for restriction or how to flush it out if possible. I am about to check my stats now, maybe some grass stuck in there. What else could I do? Thanks!

 

[Dukedog]

check stats, poppet for junk.. "add a water pressure gauge".. new pump kit for peace of mind... check over temp buzzer and run it.. temps do rise with rpm and load.. go for a very long run ta see if tha temp gauge holds steady or continues ta rise till ya get out of it or tha alarm sounds.....jmo

 

[jrocksho]

I checked my stats yesterday, they were clean and opened around 143-145 on stove. I have a pressure gauge, 20PSI WOT. I do know temps rise with RPM but never had it get that high since I owned this boat, usually stays near middle of gauge running or not. I plan on going out Saturday to test again. It seems to stay around 3/4 mark while running around 4500RPM or so but last time I was out had my little girls with me, so I couldn't go WOT lol. I did go a little faster and it raised a hair above 3/4 mark. I may check the poppet today or tomorrow, I just hate to go into it without replacing parts and I don't have the money to buy anything now lol. Thanks.

 

[jrocksho]

Ran on driveway today, water from telltale gets hot before the gauge moves. Sometimes it kinda spits water out, but I don't smell exhaust or anything in water. Could this be cylinder head gaskets? Making water hot too quick? It's not hot coming from prop or slots in mid section, just from the telltale.