force 120 overheating help

[fastaction]

OK Long story short 93 bayliner 26ft trophy twin 120 force Was sitting for 5 years and I got it for free.....
As I was leave with the boat ,the guy said something about the Buzzer going off and bye...

Well new parts
Flushed fuel tank
New fuel filter
Comp check 125 on all 4 x 2 =8
clean carbs with new kits
new Water pump kits
New thermostatas
Lower gear oil
New plugs 8
2 new coils

So any way With the New pump kits in and New thermosatats .The buzzer goes off in about 10 mins of running on 1 motor . I checked the temp of water coming out and it 168 and the Block is 180 Now the thermos i put in are 130 So ,I dont understand why It is overheating ..

Head gasket ? If so Wouldnt it effect the running of the motor?
Temp swicth ? Is there a test ?
Can you Run or make you own Tell /tale water pisser line ?

I see smoke But oil mix /steam

 

[fastaction]

Re: force 120 overheating help

Just was reading the Post on the Tell/tale Tube I will do this In the Moring and Find out if the Buzzer still goes off

 

[fastaction]

Re: force 120 overheating help

any input

 

[pnwboat]

Re: force 120 overheating help

Do you have two buzzers or just one? How can you tell which motor is overheating?

Since you have two motors, you may try switching the thermal sensors between the two and see if the problem moves. If it doesn't, then it may be a blocked, or partially blocked water passage.

Since the compression test looks good, it probably isn't the head gasket. That doesn't rule it out 100% but it's not likely. You may have some blockage in the water passages somewhere. You can try back flushing the block. To do so, you need to take the lower unit off. Remove the thermostat cover and thermostat. Take your garden hose and insert it into the opening where the thermostat sits. Take some rags to seal up the hole around the hose and turn it on. Water should flow out of the water tube. You can take a bucket and put under the water tube to catch any debris that may come out. This way you can confirm if any debris was blocking the water passages.

 

[fastaction]

Re: force 120 overheating help

It does have 2 buzzers And I installed the Tell/tale tube today... Its running now around 185 195 .. What Is really to hot for a outboard ? 200 ? 210 ?
I will try To swap out sensors and See what Happens ..the good thing is that I live on the water and the Boat is in the water ... I did notice tonight That It got hot in about 3 mins or less and Is pumping a lot of water out..

So tonight
I took the thremo out and tested it and still is hot

 

[pnwboat]

Re: force 120 overheating help

I think that 180 or 190 is too hot. It would be nice to see what kind of water pressure you're seeing at the fitting at the top of the head where the tell tale is attached. That would tell you if you're getting good pressure/flow up to that point. Do you have tell tales on both motors? If so, does the water stream coming out seem to be the same on both?

One other thing. The water exits the block right where the thermostat is located and goes into the head. There is kind of a flat water passage that runs through the head down towards the bottom of the motor and into the lower leg and out of the motor. The head is actually two pieces. One piece is a plate that actually sits on top of the head that forms the water passage. Unfortunately, all of the head bolts run through the two pieces of the head. To check for blockage here, you would have to take the head off. Not really a big deal, but sometimes the head bolts get corroded and may snap off when loosening. See items 19 and 20 in the diag. below.

http://www.boats.net/parts/search/Merc2/Force/120%20H.P.%20%281995%29/0E093700%20THRU%200E138599/CYLINDER%20BLOCK/parts.html

I wonder if you've got some mud dauber wasps that have built a nest in the water passage or something like that. You never know what you'll find in a motor that's been sitting for a long time.

 

[fastaction]

Re: force 120 overheating help

I am going to take it apart and Do head gaskets and Back flush it .. But still over heating

 

[fastaction]

Re: force 120 overheating help

Well I back flushed it today .. Didnt see anything come out ,But I did a head gasket and Exhaust gasket ..RAN the motor again and The temp is around 105 .I put it in the water ran it hard and about 30 min Went up to 165 again and the Tell/tale was shooting out air and very little water ...? what is that all about ..Got back to my dock turned the boat off and Started it again after 45 min and was run at 105 ,106 again ?? What is going on here ?

 

[pnwboat]

Re: force 120 overheating help

Have you checked the timing at WOT? I wonder if the timing is too far advanced?

 

[sentinel]

Re: force 120 overheating help

"I did a head gasket and Exhaust gasket ..RAN the motor again and The temp is around 105 .I put it in the water ran it hard and about 30 min Went up to 165 again and the Tell/tale was shooting out air and very little water ...?"

I am getting mixed impressions here. Apparently you are testing in a barrel a short time for the 105 degrees, then doing a hard run test at a dock or similar?

The key here appears to be the tell-tail water is turning to steam when the motor is run hard.

Several things come to mind.....

a) Cracked block or head which might not show low compression when engine is cooler. Recheck compression when motor is HOT quickly.

b) If the engine is in gear(prop turning at a stand-still), you might have a cavitation problem...pulling air into the water pump which will occur if boat is not in motion at high RPM.

c) If the engine is not in gear, it has to be a water jacket blockage or a failure in the pump housing or pump not delivering (enough) water which will cause steam from lack of cooling in what water might be getting in to the engine.

Not knowing (exactly) how you are testing this motors temperature and the step sequence you are doing makes it difficult. Have you done the same EXACT (EXACT stressed), hard-run test at the dock with the other motor?....Were there any differences noted in the tell-tail and temperature if you did?

Sentinel