And now it's overheating..3.0

[rparde]

Hello again,

I would like to thank everyone for their help so far. I just finished replacing my bellows, trim senders and shift cable. Everything went smoothly with the help from achris' videos and a copy of service manual 14 that Don S was kind enough to share with another member. Well I finished the bellows last weekend and took the boat out today to test the shifter and for leaks. Everything was running great until about thirty minutes into the trip. I had the boat wide open and all of a sudden the temp shot up. I immediatly killed the engine and let it sit for a while. Once the engine cooled we were able to slowly limp back to the ramp killing the engine whenever the temp fluctuated. My question is of course where to start checking....Thermostat and Water Pump? I recently bought the boat and don't know when they were done last. I thought my new raw water hose came loose but it looks fine.

My other question is in regards to the temp gauge. The gauge didn't just rise, it bounced all over the board (anywhere from 170 to 250) up and down. Whenever the guage started to bounce I would cut the engine off. It would do this at slow speeds (under 1000 rpm) also. Is this normal I would expect a steady reading. It took us forever to get in and we beat a thunder storm by minutes. I am new at this boat repair stuff and find myself pouring through manuals and videos before attempting anything so any help is appreciated. My Seloc manual has of course been usless:facepalm:.

Mercruiser 3.0 # L374668
Alpha 1 gen 2 Drive # OL460181

Thank you for any help

 

[Don S]

Re: And now it's overheating..3.0

First thing you check in any overheat situation is the impeller. All it takes is a plastic bag over the intakes for a minute and you no longer have an impeller. When you shut the engine off, the bag fell off and sank. No evidence.

 

[rparde]

Re: And now it's overheating..3.0

Thanks Don, that's where I'll start then.

 

[rparde]

Re: And now it's overheating..3.0

Looking for some more help on this issue. I relaced the impeller and am still getting the erratic temperature reading (mostly on the hot side). I have read some other posts that say to check for clogged lines but I am not sure how to go about the process. The circulating pump hose does get extremly warm after a short period of the engine running. I don't know enough about the cooling system to realize if this is normal or not. Any help in giving direction of what step should be next in tracking down the problem would be greatly appreciated.

Thanks in advance,
Ryan

 

[Speed1v8]

Re: And now it's overheating..3.0

Well I get bouncing fuel guage when I turn motor on and bounces up down like you said when it shakes must be loose wire

 

[rparde]

Re: And now it's overheating..3.0

Thanks Speed1, it looks like your on to something. I went back to the boat and turned the ignition to on and the temp was pegged at max. The thing had been sitting there untouched so I pulled the temp sender wire and the gauge didn't budge. I started tracing the wire and it was wedged against the engine under the raw water hose. The minute I pulled the wire out the guage dropped to zero. I put the wire on a ground and it maxed out again so guage seems fine. Since I moved the wire from under the hose I haven't had the problem show on the muffs yet. Hopefully that is the problem.

I'm eager to do a water test but now the boat won't idle so it seems that I have more work to do. Thanks again for the tip.

 

[Harritwo]

Re: And now it's overheating..3.0

I had a similiar problem with a 3.0L. It turned out that the temp sending unit wire was hitting the pulley and grounding out causing the guage to read hot. Check to make sure that your wire is tight and not touching metal anywhere.

 

[ktbarrentine]

Re: And now it's overheating..3.0

My Seloc manual has of course been usless:facepalm:.

Slowly people are realizing that about the only thing this manual is good for is starting your camp fire.... and the "good" manual is right here on this forum....for free! :facepalm:

 

[Speed1v8]

Re: And now it's overheating..3.0

But we are here help. But anyway yea check wires to be good I just scrubed the wire cleaned it and connected it tight no bounce know.