Boat Engine Cutting Out

[meder24]

So a month into owning my first boat, I am having my first issue. I have an '87 Thompson w/ the 3.0L Mercruiser. My cousin let us use his dock space for a few weeks while I got my trailer repainted. So the boat was in the river for 2 weeks. We did use it a few times while in the river but nothing much.
So last weekend, 2 weeks after we put it in the water, we take it out and run it for the first time in about a week. About 15 minutes after cruising higher than idle, the engine cuts out entirely and all electrical components shut off. I then was unable to get the engine to re-fire for a good 5 to 10 minutes. Once started we were able to cruise again for about 10 minutes before the same issue occurred.
The out drive was pretty dirty from being in the water so I initially assumed that maybe it was not bringing in enough water to cool the engine and it was cutting out because of this.
However, the more I read into this, it seems like it is either an electrical issue with possibly the ignition or water in the fuel somehow. Both of these seem more likely to me as some water did get into the boat since the cover we had on it partially came off during a storm.
Anyone had a similar issue and what did you do to fix it?

 

[DeepBlue2010]

Water should not get in the gas tank just because the boat cover was off. It could however seep into the tank through a loose cap (bad O-ring or the cap simply not tightened enough) or a loose fitting on top of the gas tank if water can find its way to the top of the tank. You can find out if you have water in your gas by taking the fuel/water separator (a.k.a fuel filter) and dump it in a transparent container. If water is present, it will separate on the bottom of this container and you will be able to see the separation between water and fuel easily. Best of luck to you

 

[Bondo]

So a month into owning my first boat, I am having my first issue. I have an '87 Thompson w/ the 3.0L Mercruiser. My cousin let us use his dock space for a few weeks while I got my trailer repainted. So the boat was in the river for 2 weeks. We did use it a few times while in the river but nothing much.
So last weekend, 2 weeks after we put it in the water, we take it out and run it for the first time in about a week. About 15 minutes after cruising higher than idle, the engine cuts out entirely and all electrical components shut off. I then was unable to get the engine to re-fire for a good 5 to 10 minutes. Once started we were able to cruise again for about 10 minutes before the same issue occurred.
The out drive was pretty dirty from being in the water so I initially assumed that maybe it was not bringing in enough water to cool the engine and it was cutting out because of this.
However, the more I read into this, it seems like it is either an electrical issue with possibly the ignition or water in the fuel somehow. Both of these seem more likely to me as some water did get into the boat since the cover we had on it partially came off during a storm.
Anyone had a similar issue and what did you do to fix it?

Ayuh,.... That sounds Electrical, not fuel related,.....

Start by cleanin' to shiny metal Clean the electrical connections, from the battery to the starter, 'n the grounds,...

One way to Find the problem, is go out, 'n do it again, only bring yer test light or multimeter, 'n See where there's Power, 'n where it Stops,....

 

[alldodge]

So a month into owning my first boat, I am having my first issue. I have an '87 Thompson w/ the 3.0L Mercruiser. My cousin let us use his dock space for a few weeks while I got my trailer repainted. So the boat was in the river for 2 weeks. We did use it a few times while in the river but nothing much.
So last weekend, 2 weeks after we put it in the water, we take it out and run it for the first time in about a week. About 15 minutes after cruising higher than idle, the engine cuts out entirely and all electrical components shut off. I then was unable to get the engine to re-fire for a good 5 to 10 minutes. Once started we were able to cruise again for about 10 minutes before the same issue occurred.
The out drive was pretty dirty from being in the water so I initially assumed that maybe it was not bringing in enough water to cool the engine and it was cutting out because of this.
However, the more I read into this, it seems like it is either an electrical issue with possibly the ignition or water in the fuel somehow. Both of these seem more likely to me as some water did get into the boat since the cover we had on it partially came off during a storm.
Anyone had a similar issue and what did you do to fix it?

:welcome: to iboats

Agree with Bondo, it's sounds electrical. When it dies, can you crank the engine over and it won't start or do you get nothing when the key is turned?

 

[meder24]

Thank you for the replies. When it dies on me I am able to immediately crank the engine it just does fire up for 5 to 10 mins. I will definitely clean the connections tomorrow and take me volt meter to see what's going on if the problem persists tomorrow.

 

[camalot]

Something else to check is the fuel tank breather, if it happens after a given time each time it,s points to a fuel problem lack off.

 

[Lincoln253]

Is there a thermal breaker anywhere on it.... It could be getting hot tripping it and then working again after it cools and resets

 

[Weskitoo]

Electrical problems are tough. My boat was cranking over all by itself.
I was in my house and I heard my boat trying to start. I thought kids might be playing in it. I went out and looked and the mooring cover was all snapped tight and the engine was cranking over. My problem was moisture in the assist solenoid.

 

[meder24]

I can only find the circuit breaker as shown below. I did not check it when the issue occurred. Seeing as the engine will crank and all electrical components will turn on immediately after it stalls but just will not start leads me to believe its more fuel or temp related than electrical but that's just my hopes. I added some fuel treatment as well as plan on testing electrical components today if the problem persists.

 

[Lincoln253]

How consistantly is the problem happening

 

[meder24]

Well I had the boat out for about 4 hours today of cruising and she never stumbled once. No stalling or shutting off. I did flush the engine with clean tap water as it was awfully dirty from being left in river before putting it in the river today. So no issues today. One thing I did notice was the engine temp gauge was showing a temp about 15 degrees lower than normal. Now the river is significantly colder than it was a few weeks ago. But Is the drop in water temp enough to show this change?

 

[redneck joe]

what is the temp showing? SHould be around 165-180 for most IO's I think

 

[meder24]

When we bought the boat and the first few times we had it out, the temp would run a bit under 160 when moving around. It would obviously go up a bit once we stopped and then eventually drop down to back around 160 or less if still just idling.

 

[alldodge]

You have a carb engine and with that the normal thermostat would be 140 degrees. It will run a bit hotter then 140 when under heavy load or right after slowing down but should drop back. I don't see the lower temp causing the engine to cut out.

Your engine will crank so it is not the 50amp circuit breaker. As for the original problem I'm still leaning toward electrical. The engine will crank but is it getting spark? The next time it does it pull the coil wire and see if it's getting spark. If it was fuel it would die out slowly and cough or sputter then die .

 

[meder24]

Thank you for the information, AllDodge.
I am hoping I can get the boat out once again this year as despite running fine this past weekend, I am not totally sold.
Checking the spark is a great idea. I was planning to replace the dist. cap and wires this winter, since I am not entirely sure how old they are. Might be worth trying now if I can get the problem to occur once again.