Force 120 Overheats

[MikeyB3649]

I've changed the impeller, gaskets, impeller housing, water tube grommet, thermostat and all associated seals/gaskets, flushed the water lines, and it still overheats on muffs at around 15 mins. Anybody have any ideas?

 

[MikeyB3649]

Re: Force 120 Overheats

Ok. So I added a tell tale and I get about a 1 foot stream at idle. When I run it up, it shoots out about 3 or 4 feet. Seems to me the pump is working strong. Any other ideas?

 

[pnwboat]

Re: Force 120 Overheats

It's not unusual for the hose w/muffs to not supply enough water to cool the motor. You might try using some duct tape to seal the muffs, or try a large container that will allow you to submerge the lower end up to the cavitation plate.

If that doesn't help, perform a compression test on all cylinders to see if the head gasket is sealing properly.

 

[foodfisher]

Re: Force 120 Overheats

What's telling you that it's overheating? Can you rest your hand on the head? Try a thermometer in the telltale stream.

 

[MikeyB3649]

Re: Force 120 Overheats

The overheat buzzer tells me it overheats.

When it overheats I can't keep my hand on the head for more than a couple seconds. Prior to that, I can hold my hand on it for around 5 or 6 seconds.

I took it to the lake today and tied off to the dock and ran it. After about 15 minutes at idle, it overheated again. I haven't tried moving around yet because I don't want to get too far and have to limp it back to the dock. I did notice that I have an exhaust leak into the cowl. It ran fine with the cowl off but as soon as I put it back on, it overheated about 5 minutes later. Maybe the exhaust is leaking back into the carbs and overheating it? Also, I got home and taped off the muffs and noticed that I have water shooting from weep holes on either side of the lower unit and a very heavy stream of water flowing from the prop.

I went to do a compression test and found my gauge is busted so I have to run down to Autozone and rent one of theirs.

And if things weren't bad enough, I found one of my spark plug ends broken off so I have to track one down. In my neck of the woods, it's not easy to find the L76V's.

With that new info, any more suggestions?

 

[MikeyB3649]

Re: Force 120 Overheats

Also, it is a new head gasket and new head bolts torqued to spec from the manual.

 

[MikeyB3649]

Re: Force 120 Overheats

Ok compression is as follows from top to bottom.

130
130
130
127

Changed the broken spark plug and attempted to tune the carbs as per the manual. Got it to idle around 500rpm.

Water temp sensor straight off the tell tale port reads from 127 to 134F. Temp inside the cowling reads up to 118F. I ran it for about 35 minutes with the cowling off and then for about 25 with the cowling on. Never overheated once.

I'm off to the lake to try once more before sunset. Winds are around 35-45 mph.....this is gonna be a bumpy ride.

I'll post after the trials.

 

[MikeyB3649]

Re: Force 120 Overheats

Ok. Got it out on the lake and ran it around for like 45 mins without overheating. The only thing I noted was that it idles around 450-500rpm and since it's that low, it tends to die when I put it in forward or reverse. I'll work on that later. For now though, I've got one major hurdle take care of.