1984 140 horse mercruiser cuts out after a few minutes.

[rolmops]

Ok a little history.
I replaced some piston rings,the head gasket and the manifold gasket.Also replaced is the water pump and from points I changed it to electronic ignition.
So I thought that this thing would behave and indeed she starts just fine,but after running for about 5 minutes it cuts out and refuses to start for quite a while,and then she will start again and run for a few minutes. So my first thought was "Effing water in the tank" and I opened the water separator and drained it, but the same thing happened again.Next theory was "ah maybe a thermostat that stays shut causing the engine to over heat and activating the overheat shut off". So out goes the thermostat and the next try is without a thermostat.Same thing,she starts up and runs for a few minutes and stalls.Maybe a blockage in the raw water supply? So down came the lower unit and all the water lines are checked for blockages and there are none. Tomorrow I will take the lower unit raw water pump apart to check it even though it is new.
Is over heating my problem? Should I replace the upper water pump? Or did the change from points to electronic ignition have some unintended side effects?
I am at a loss and really can use some expert advice on this one,so please give your thoughts and opinions.
Thanks,Cornelis

 

[Howard Sterndrive]

Re: 1984 140 horse mercruiser cuts out after a few minutes.

never seen a high temp shutdown system on an 84.
what does the temperature gauge say?

 

[generator12]

Re: 1984 140 horse mercruiser cuts out after a few minutes.

Ok a little history.
I replaced some piston rings,the head gasket and the manifold gasket.Also replaced is the water pump and from points I changed it to electronic ignition.
So I thought that this thing would behave and indeed she starts just fine,but after running for about 5 minutes it cuts out and refuses to start for quite a while,and then she will start again and run for a few minutes. So my first thought was "Effing water in the tank" and I opened the water separator and drained it, but the same thing happened again.Next theory was "ah maybe a thermostat that stays shut causing the engine to over heat and activating the overheat shut off". So out goes the thermostat and the next try is without a thermostat.Same thing,she starts up and runs for a few minutes and stalls.Maybe a blockage in the raw water supply? So down came the lower unit and all the water lines are checked for blockages and there are none. Tomorrow I will take the lower unit raw water pump apart to check it even though it is new.
Is over heating my problem? Should I replace the upper water pump? Or did the change from points to electronic ignition have some unintended side effects?
I am at a loss and really can use some expert advice on this one,so please give your thoughts and opinions.
Thanks,Cornelis

The first thing I'd look at is whether I'm missing either spark or fuel when she shuts down. If you find either missing, you'll have a trail to follow. Without this information you'll continue to throw parts at it and hope!

Next time you can get it to the stopping point, remove your flame arrestor (or whatever you have on this engine) and see if the carb is dry. If so, there's your starting point. (You could even spritz a little gas into it from a can and see if she tries to light up.) If not, turn it over and see if you can get spark from the coil wire to engine ground. If not, there's the place to begin. If so, then you may have internal problems. But this is the basic approach to troubleshooting it.

 

[rolmops]

Re: 1984 140 horse mercruiser cuts out after a few minutes.

It turned out that there was over 3 gallons of filthy water in the tank. I removed all the water and the old fuel and refilled the tank with pure gasoline. On top of that I replaced the carburetor and now she is running like a dream.
She will have another water trial in a few days.

 

[Bondo]

Re: 1984 140 horse mercruiser cuts out after a few minutes.

It turned out that there was over 3 gallons of filthy water in the tank. I removed all the water and the old fuel and refilled the tank with pure gasoline. On top of that I replaced the carburetor and now she is running like a dream.
She will have another water trial in a few days.

Ayuh,..... Funny how that water just won't burn,.... ain't it,..??

Also to bad that We can't buy Real gasoline anymore either....

I'd suggest ya buy a canister type filter, 'n put it just ahead of yer fuel pump,...
It'll go Along ways in helpin' ya Keep it runnin' smooth, in the future....
Don't wanta get any water in that New carb....

 

[rolmops]

Re: 1984 140 horse mercruiser cuts out after a few minutes.

Ayuh,..... Funny how that water just won't burn,.... ain't it,..??

Also to bad that We can't buy Real gasoline anymore either....

I'd suggest ya buy a canister type filter, 'n put it just ahead of yer fuel pump,...
It'll go Along ways in helpin' ya Keep it runnin' smooth, in the future....
Don't wanta get any water in that New carb....

That is true!Water does not burn!
As for the fuel,within a 4 mile radius of my house, there are four gas stations where 91 octane unlaced gas is sold and a fifth one where I can buy 87 and 91 pure gas.
Most fast trac stations stopped selling 93 and put pure gas in those tanks instead.
With the nation wide drought severely cutting into the corn supply we will see that the farmers will keep their corn to feed live stock and the corn prices will go so high that it will be very un-economical to keep on making ethanol. My feeling is that the ethanol hoax will die a quick natural death. Most politicians both left and right wanted to stop it,but they were afraid of alienating the farmers lobby. The drought has taken care of it for them.
As for the canister type filter, right now I have a canister type water separator, a screen fuel filter in the fuel pump and another screen at the entrance to the carb. Do you suggest a canister right after the water separator?
On another note,
Last week we ran into the Chaumont river on our way from the shipping canal near Duck Island back to the Little Salmon just to get the feel of the Islands.

 

[Bondo]

Re: 1984 140 horse mercruiser cuts out after a few minutes.

That is true!Water does not burn!
As for the fuel,within a 4 mile radius of my house, there are four gas stations where 91 octane unlaced gas is sold and a fifth one where I can buy 87 and 91 pure gas.
Most fast trac stations stopped selling 93 and put pure gas in those tanks instead.
With the nation wide drought severely cutting into the corn supply we will see that the farmers will keep their corn to feed live stock and the corn prices will go so high that it will be very un-economical to keep on making ethanol. My feeling is that the ethanol hoax will die a quick natural death. Most politicians both left and right wanted to stop it,but they were afraid of alienating the farmers lobby. The drought has taken care of it for them.
As for the canister type filter, right now I have a canister type water separator, a screen fuel filter in the fuel pump and another screen at the entrance to the carb. Do you suggest a canister right after the water separator?
On another note,
Last week we ran into the Chaumont river on our way from the shipping canal near Duck Island back to the Little Salmon just to get the feel of the Islands.

Ayuh,.... Couldn't remember if ya had that filter, or not....

Been some weird winds on Chaumont Bay the last few weeks,...
Glad they were blowin' on them, Hot days....

That's a pretty fair stroke of a boat ride,....

 

[rolmops]

Re: 1984 140 horse mercruiser cuts out after a few minutes.

That's a pretty fair stroke of a boat ride,....

We have been known to go a long way looking for kings.

 

[rolmops]

Re: 1984 140 horse mercruiser cuts out after a few minutes.

SO I got the Islander on the water again for some more trials and so far the news is good. All the leaks are fixed. Having replaced 4 rivets with bolts and nuts laced with M5200 took care of that. The engine starts well and runs well although there is an issue with a stiff cable that forces me to manually push the rod at the carb in order to achieve idle at 600 instead of 1200 rpm. Another thing yet to be solved is the charge.
When I start her up she charges between 13 and 14 volts ,but after a while that goes down to less than 12 and that is not so good. Any suggestions as to what to look for on that one?
Then there is the exact angle of the drive shaft and the engine block. It was all set and smooth, but now that I ran her at WOT she sounded like she is out of alignment, so I'll have to tweek that a bit. She topped out at 25mph and that is plenty fast for a fishing rig.
Over the weekend there will be time to do the tweeking.
Rolmops.