85 hp shut down at 2000 rpm

[Pan84]

Hi every one !
I was on the water today, and test my boat (it is my first boat and ride, it is very difficult to get on a trailer )
1987 85 hp mercury force shut down at 2000 rpm, it is wrong timing ?
And one more question, when engine ran, i had steam from 2 hole on motor leg, it is ok? impeller is new and water flow good from telltale. It is possible to install the temperature gauge on these motor? if yes where it should be?

 

[Frank Acampora]

Re: 85 hp shut down at 2000 rpm

Good evening, Pan. My father was Napolitano, but my family traces its ancestry to the town of Campora.

You should NOT see steam coming from the two holes. These holes are the idle relief and reduce backpressure when the engine is sitting low in the water. This keeps it from stalling. However, cooling water does exit from them.
If you are seeing steam rather than water--either a spray or a stream--then it indicates that the water pump is not supplying enough water. You need to drop the lower unit and replace the rubber impeller.

Again, if you were seeing actual steam, not a spray of water, it is highly likely that the engine overheated and stalled. The RPM was not significant.

If this is the case, before you do anything else, check the compression to be certain no damage was done to pistons or cylinder liners. Compression should be at lease 100 PSI preferably125 to 150 and equal on all three cylinders. Sorry, I do not remember the metric equivalent of PSI.

 

[Pan84]

Re: 85 hp shut down at 2000 rpm

The engine not shut down after I see the steam. Every time, even if motor cold on 2000 shut down. And start nice after. Steam mixed with water spray. Impeller was new

 

[Pan84]

Re: 85 hp shut down at 2000 rpm

No any idea why shut down on 2000 rpm?

 

[foodfisher]

Re: 85 hp shut down at 2000 rpm

Don't know if it's even possible, but could the neutral safety switch be in the wrong place?

 

[pnwboat]

Re: 85 hp shut down at 2000 rpm

I would suspect that it's either not getting enough gas or no spark. Have you tried squeezing the primer bulb to see if that has any affect? If it does, then I would replace the fuel pump diaphragm.

 

[Pan84]

Re: 85 hp shut down at 2000 rpm

No I dont try squeezing the primer bulb

 

[pnwboat]

Re: 85 hp shut down at 2000 rpm

Try it and see what happens. If the motor runs better, then you probably have some type of fuel delivery problem. Could be a bad fuel pump (bad diaphragm or check valves), a restriction in the fuel line, or debris in the gas tank that is restricting the fuel pick up tube. Could also be a bad primer bulb.

Yes you can install a temperature gauge. Here is where I installed the temperature gauge sending unit on my motor. There is a small plug just above the thermostat housing that opens up to the water passage in the block. Remove the plug and install the sending unit. Just one word of caution. These motors run relatively cool as compared to 4 stroke automotive engines. Maybe 150 degrees F maximum (66 degrees C). Most standard 4 stroke water temp. automotive gauges do not read that low.

 

[john from md]

Re: 85 hp shut down at 2000 rpm

Pan,

Is the engine running rough before it shuts off? If not, I suspect that maybe you have some loose wires under the flywheel that are shorting out as the timing trigger is advanced. This is not uncommon on older engines as the wire ties break from age.

If it starts running rough before it shuts off, I suspect a fuel delivery problem.

Giovanni Michelli from Pescara a long time ago.

 

[Pan84]

Re: 85 hp shut down at 2000 rpm

No, the engine running good, just slow down and stop. I was checking compression (130 each) and timing. Timing mark was about 1 inch away of the TDC. I hope these is was problem?
All wires under flywheel looks good.