Mercury 40hp died on the water

[duckweed]

Saturday I spent a good part of the day on the water and the motor ran fine all day. Then when we were headed in I hit a decent sized wake and the motor died. We were in sight of the ramp. The fuel bulb would not prime back up. It still had plenty of fuel in the tank(maybe 1/2 a tank). I trolled it in and managed to get it loaded. Once I got it home the fuel bulb primed back up and it ran fine.

This is a motor that sat up for about 10 years, I have been in the carbs 3 times in the last few months. Do you think a float stuck or just a fluke with the bulb on the tank? If I get a chance this weekend I will see if it will duplicate the problem. It is currently running really good and I hate to pull the cabs again but cant have a motor that's is not dependable.

This is a 1991 Mercury 40hp 4 cylinder with 2 carbs. Does anybody have any ideas on what to look for or suggestions?

Thanks,
Nathan

 

[Bailey Boat]

Before I began heart surgery (carbs) I would replace the primer bulb. They have a finite life span and are cheap and easy to replace.

 

[duckweed]

The bulb and the tank are fairly new. There has only been two tanks of fuel thru them. The bulb will prime up hard as a rock right now, but wouldn't the other day on the water for nothing. I just don't feel like the bulb is the problem, but I will give it a try. If it is not the problem it cant hurt to have a extra one laying around.

Thanks

 

[TNtroller]

Check all of the clamps on the fuel hoses as you apparently have a air leak somewhere since the bulb would not get firm the other day. It doesn't take much to cause an air leak in the gas lines.

 

[perchjerker]

my money is on the float hanging up

were you smelling gas when you were pumping the bulb?

gas dripping from a carb?

what do you mean you "trolled it in"?

was the motor running or did you use another motor?

vent on the gas tank wide open?

could very well be the bulb, they just have cheap plastic components on them and a weak spring

 

[JL8Jeff]

It could have been the fuel line popped loose at the connector or air was getting in. Or an air bubble got stuck in the tank pickup due to the bounce over the wake.

 

[duckweed]

I did not notice or smell any gas, and I called myself looking because I figured it was a float issue and expected gas to be coming out of the vent on the carb. I used the electric trolling motor to make it to the ramp. The part that has me stumped is that is has fixed itself(for now) and I cant find the problem unless it does it again.

Thanks

 

[wmk0002]

My recommendation is to install a clear fuel filter between the fuel pump and the carb. If the motor fails on you again and the bulb goes soft, remove the cowl and check out the filter. If it is full of fuel you are delivering fuel to the carb but your float has likely gotten stuck. If that were the case you should see fuel coming from the weep hole and have a strong gas odor coming from the spilled fuel. If the filter is empty you have an air leak in the fuel line somewhere or malfunctioning primer bulb.

 

[perchjerker]

I did not notice or smell any gas, and I called myself looking because I figured it was a float issue and expected gas to be coming out of the vent on the carb. I used the electric trolling motor to make it to the ramp. The part that has me stumped is that is has fixed itself(for now) and I cant find the problem unless it does it again.

Thanks

sounding more like a flaky primer bulb check valve maybe. If you did not see any gas coming out of the carb vent then I would rule out sticking floats.

I have also seen problems with the quick connect for the fuel line at the engine, a bad o ring could cause issues

are you sure the fuel tank is clean? No water or sediment in the bottom?

just throwing some stuff out there

 

[billyjoebigdaddy]

When you hit that wake did your primer bulb fall sideways? Reason I'm asking is a lot of the fuel primer bulbs have stop balls in them(Don't know what the real name is). It allows fuel to flow when the arrow on the side is pointing up but if the bulb falls on its side or pointing down the ball will fall and block the fuel...

 

[duckweed]

Thanks for the ideas and advice. The motor has ran fine ever since and has not gave me any more problems. I am just going to run it and see if it happens again.

Does any one know about how fast this motor should push a 1651 polar kraft? The best I have been able to obtain is right around 20mph at WOT. Does this sound about right? It is a heavy boat and always has me, my two boys and gear aboard (400lbs maybe).

 

[duckweed]

I took the boat back out this weekend and it messed up again. This time it had fuel dripping from the bottom of the lower carb. The fuel appeared to be coming from inside of the carb and not the vent hole. When I got home I removed the carbs. The more I messed with it the more fuel that poured out of it. I removed and broke down the bottom carb at least 3 times moving the float each time. I'm hopping the needle is bad or hard or something so I went ahead and ordered two carb kits. I have only installed a gasket kit thus far and not a full carb kit. I hope this solves some of my issues. I am sure the biggest problem this motor has is its mechanic.

It will run but not idle with the fuel leaking out. Does this sound about right? Assuming I rebuild the carbs correctly do you think this will help with my problems?

If a place to buy a motor had been opened Saturday afternoon I would have probably purchased a new motor and I would be regretting spending the money today......thank goodness everything was closed and my frustrations have faded some.