1986 Mariner 150hp overheating questions from a NEWB!

[dropnbassonu]

Hi,

I am not the most handy when it comes to engines, etc. So, I know this forum has alot of intelligent people that can help me out! Here is my problem:

I checked my motor today. I cranked it up and let it idle for 15 minutes. It was peeing. After idling it did not overheat at all. Temperature gauge was at 1/3. I pulled it out of the slip and made a circle. Within 30 seconds the temperature gauge had gone from the left 1/3 of the gauge to the 2/3, and fast approaching the far right.

So, with that info, does anybody have any suggestions? Also, any approximate prices I should expect to hear from the mechanic if I take it in?

Thanks for your time!

 

[jackd1023]

Re: 1986 Mariner 150hp overheating questions from a NEWB!

I would first get a new impeller and thermostat, Pretty easy job, Buy a manual and go to work.

From my experience this time of year most reputable marinas are swamped with work this time of year, up to a month waitin list.

Price depends on region and shop hour rate, Here is Chicago area up to $125 hr.

If you are somewhat handy and can follow directions, you can do it yourself in an hour or so.

Good luck any problems just post and someone will help you through it.

 

[dropnbassonu]

Re: 1986 Mariner 150hp overheating questions from a NEWB!

Ok, update......

Took it out yesterday and I could put it into gear and idle at 3 or so mph all I wanted to without it getting too hot. Stuck thermostat? Water pump going bad? Somebody at work told me to take the cover off, run it til the gauge says it is hot, then go back and touch around just above the plugs to make sure it is indeed running hot?

Are there any other ways of checking to see if it might be faulty wiring, or if it might actually be something wrong? I am trying to not take it in to a mechanic, b/c I don't want to get hosed for $100 in labor when it only really takes 5 minutes to fix.

 

[RaScLeS]

Re: 1986 Mariner 150hp overheating questions from a NEWB!

if the motor is peeing when your using it the damn thing should be cooling fine. does not make sense to me. unless the tstat closes when under load :S

 

[j_martin]

Re: 1986 Mariner 150hp overheating questions from a NEWB!

Assuming it's a V6,
It could have a good stream and still be overheating, if the poppet is stuck or some water exit ports are clogged.

The best troubleshooting data can be had from a pressure gauge. It's also your best indicator of cooling system condition, well worth the fifty bucks or so to in stall it.

If either of the above conditions are true, I'd expect to see excessive pressure, and it would have a strong stream.

 

[Arkman]

Re: 1986 Mariner 150hp overheating questions from a NEWB!

Assuming it's a V6,
The best troubleshooting data can be had from a pressure gauge. It's also your best indicator of cooling system condition, well worth the fifty bucks or so to in stall it.

Can you briefly describe the install. I would assume you install this right in line with the tell tail stream. Is this correct?

 

[j_martin]

Re: 1986 Mariner 150hp overheating questions from a NEWB!

Can you briefly describe the install. I would assume you install this right in line with the tell tail stream. Is this correct?

Nope, not at all.

On top of the engine, just aft the flywheel, there's a pipe threaded hole, with either a plug in it, or a hose from it going down to the poppet valve on the starboard side of the engine. You either tap into that hose, or install a hose barb where the plug is for the small plastic line that goes up to the gauge.

The pressure in the tell tale stream is not a good indicator of engine water pressure.

Oh, that's right. You're a newbie.
Aft is behind
Starboard is the right side.

hope it helps
john