Temp rising

[smithrock]

I installed a new engine recirculation pump and I noticed that my temp is reaching 220+ at times before going back to 160. I'm thinking maybe some material or something got into the thermostat not allowing it to open? All the water was drained out at the time, that's why I'm thinking maybe some sediment got dislodged. Maybe I need a new thermostat, before I changed the pump the thermostat would open at 160 pretty much right on the money.
Any ideas?

 

[Don S]

Re: Temp rising

While you have the drive off replacing your lower shift cable, you might consider changing the raw water pump impeller in the drive.

 

[smithrock]

Re: Temp rising

I just changed it last July. I'm puzzled as to why when I had the water drained out it started now. I ran water through the muffs for atleast 15 to 20 min. before I fired up the engine just to make sure I had water in there. It did take about 10 to 15 seconds before water came out the exhaust--does that tell you anything?

 

[smithrock]

Re: Temp rising

My bad- I replaced the water pump that is located in the lower unit. The rest of my previous post is accurate as far as making sure I had water running through it.

 

[Don S]

Re: Temp rising

Pull the thermostat and check it, it may just be sticking. I gave you a link to the manual for your engine, it tells you how to check it.

 

[smithrock]

Re: Temp rising

Thanks! I'll check it, if it's manual #6 I bought one off ebay a few weeks ago. I figured I'd need it

 

[Don S]

Re: Temp rising

The engine manual. Look at your other post. #6 is for the drive.

 

[smithrock]

Re: Temp rising

10-4

 

[smithrock]

Re: Temp rising

If I do need a new thermostat, what temp should I be looking for? Also, does it need to be marine specific?

 

[Don S]

Re: Temp rising

Merc PN 807252T 1
140? Yes, it's a marine stat.

 

[smithrock]

Re: Temp rising

Thanks, Don.

Can I get it at Napa?

 

[smithrock]

Re: Temp rising

I took out the thermostat and tested it, it looked to be working fine. I'm going to go ahead and buy a 140 temp thermostat and replace it. I'm going to test it again (this time on the boat with the 160) with the muffs on tomorrow and check the temp. I have an infared temp gun. Where exactly should I be aiming the gun to get a good read? What are acceptable temps to be looking for?

 

[tic]

Re: Temp rising

You're going to have to test the T-stat out of the housing in a pot of hot water.. Put it on the stove and shoot it w/ your temp gun.. Should open at the stamped temp on the bottom of the T-stat..I just replaced one.. It had bits of rubber lodged in the spring from a previous impeller failure keeping it from opening.

 

[smithrock]

Re: Temp rising

Did you read my post? I did take it out, and tested it!

 

[tic]

Re: Temp rising

sorry, I read that you were going to test the T-stat when it was in it's housing, on the boat.. Was wondering how you were going to do that.. LOL.. misunderstanding. I'm sure you meant you'll test it on the boat by using the water temp guage on the dash..

 

[smithrock]

Re: Temp rising

sorry, I read that you were going to test the T-stat when it was in it's housing, on the boat.. Was wondering how you were going to do that.. LOL.. misunderstanding. I'm sure you meant you'll test it on the boat by using the water temp guage on the dash..

No, not at all. Why would I use the dash gauge. How do I know that the gauge is accurate?

 

[smithrock]

Re: Temp rising

bump

See post #12

 

[Don S]

Re: Temp rising

I just changed it last July.

That makes your impeller a year old, time to look at it again. All it would take is a plastic bag over the intake for a bit to toast it.

I have an infared temp gun. Where exactly should I be aiming the gun to get a good read?

Right next to the temp sender if you are wanting to compare temps.

 

[smithrock]

Re: Temp rising

That makes your impeller a year old, time to look at it again. All it would take is a plastic bag over the intake for a bit to toast it.



Right next to the temp sender if you are wanting to compare temps.

Don-

I did it using the infared gun next to the temp sender, under operating temp the the gun read between 155 and 177 and various times while the gauge was showing anywhere between 160 and 210. I am going to go ahead and buy a 140 and see what that gets me. Does the variation in temps between the gun and the gauge tell you anything? It seemed to climb higher (quickly) when I brought up the rpm's a couple times for a rew seconds.

 

[Don S]

Re: Temp rising

I would bet your IR gun is a lot more accurate. Pull the wire off the sender on the engine and test the resistance of it when the temp gauge shows 210. Check in the manual, it should give ohm ranges for the sender. Probably have the wrong type sender more than it's going bad.
The temp on the thermostats is when it starts to open. Underload, the 140 may very well be about the same or maybe only 10 degrees lower.