Boat dies out of the hole under load

[ScottieScott]

I have had this issue for a couple of years now. When my boat is full of people, or pulling a tuber, and I hit the gas out of the hole, the boat sometimes dies - not every time, but about 35-50% of the time. Since this started I got a new carburetor and fuel pump, as to me, it sounded like it was starving for fuel. This never happened with just me in the boat.

I have done a couple of things this hear that I hadn't tried before.

1. The fuel pickup tube in the tank looked like the previous owner made it himself - he worked in a machine shop. I think an issue there is he made the tube so long, that it possibly touched the bottom of the tank, and the only fuel inlet was a couple of 1/8 inch half circles filed into the bottom of the tube. It could be that a full boat requires more gas out of the hole and the pickup tube wasn't pulling enough gas. I have since cut about 1/4 inch off the tube and added an in-line filter. I would like to hear comments on this.

2. This year I replaced the shift cable. The old one was pretty stiff, and looked like it hadn't been replaced in quite a while. The aluminum end that inserts into the outdrive did not spin freely and the allen screw at the end was rusted. (I replaced the shift shaft seal so hopefully no more water in there). Before replacing the shift cable, the interrupt switch would fully engage when shifting in revers and kill the engine.

Here is my main question......Is it possible that with a full boat, there was more resistance on the prop, therefore causing the shift cable to 'stick' and engage the interrupt switch when getting out of the hole?

I am testing the boat this weekend for leaks, and to ensure proper shifting.

BTW - boat is a 1985 Sunbird with a Mercruiser 170....Alpha One Gen 1 Outdrive. Just replaced the dist cap, rotor, plugs, wires, and put in a Pertronix I with a Flamethrower coil....Starts up easily, but idles high. I am going to start another thread about idle speed tho.

Thanks,
Scott

 

[alldodge]

When you take off is this from neutral to full out or are you putting it in gear, taking the slack out then full out?

I don't see the size of the line being the issue, your burning more fuel pulling out of the whole and running hard pulling a heavy load then the initial start.

 

[Bondo]

I have had this issue for a couple of years now. When my boat is full of people, or pulling a tuber, and I hit the gas out of the hole, the boat sometimes dies - not every time, but about 35-50% of the time. Since this started I got a new carburetor and fuel pump, as to me, it sounded like it was starving for fuel. This never happened with just me in the boat.

I have done a couple of things this hear that I hadn't tried before.

1. The fuel pickup tube in the tank looked like the previous owner made it himself - he worked in a machine shop. I think an issue there is he made the tube so long, that it possibly touched the bottom of the tank, and the only fuel inlet was a couple of 1/8 inch half circles filed into the bottom of the tube. It could be that a full boat requires more gas out of the hole and the pickup tube wasn't pulling enough gas. I have since cut about 1/4 inch off the tube and added an in-line filter. I would like to hear comments on this.

2. This year I replaced the shift cable. The old one was pretty stiff, and looked like it hadn't been replaced in quite a while. The aluminum end that inserts into the outdrive did not spin freely and the allen screw at the end was rusted. (I replaced the shift shaft seal so hopefully no more water in there). Before replacing the shift cable, the interrupt switch would fully engage when shifting in revers and kill the engine.

Here is my main question......Is it possible that with a full boat, there was more resistance on the prop, therefore causing the shift cable to 'stick' and engage the interrupt switch when getting out of the hole?

I am testing the boat this weekend for leaks, and to ensure proper shifting.

BTW - boat is a 1985 Sunbird with a Mercruiser 170....Alpha One Gen 1 Outdrive. Just replaced the dist cap, rotor, plugs, wires, and put in a Pertronix I with a Flamethrower coil....Starts up easily, but idles high. I am going to start another thread about idle speed tho.

Thanks,
Scott

Ayuh,..... Welcome Aboard,.... That's a Classic symptom of a draggin' lower shift cable,......

The diptube length, I see as a Non-issue, the carb's bowel is Full on launch, the diptube is too far Upstream to matter at that point,...
If it were an Issue, it'd be at extended Wot runnin',....

 

[ScottieScott]

Thank you. I appreciate the time you have taken to answer. I have replaced the lower shift cable, and will be testing it this weekend. I think that is the answer to the issue.

Thanks,
Scott