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Jason
Jason, Marine Mechanic
Category: Boat
Satisfied Customers: 14288
Experience:  Degree in Marine Technology. Gas and diesel marine mechanic.
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Stalling at high end, well it starts out fine and as I

Customer Question

stalling at high end
JA: Sometimes things that you think will be really complicated end up being easy to fix. The Marine Mechanic I'm going to connect you with knows all the tricks and shortcuts. Tell me a bit more about what's going on so the Marine Mechanic can help you best.
Customer: well it starts out fine and as I throttle up it starts to lack and finally dies , its a 1984 approx. mercury 115 hp.
JA: Is there anything else important you think the Marine Mechanic should know?
Customer: no , not now that I can think of
Submitted: 1 month ago.
Category: Boat
Expert:  Jason replied 1 month ago.

Hello my name is ***** ***** am I speaking with?

I read what you wrote, have you done any troubleshooting on your own yet? Have you ever personally seen the motor run correctly?

Expert:  Jason replied 1 month ago.

Are you still with me?

Customer: replied 1 month ago.
I'm still here . Yes , been trouble shooting , checked plugs, fuel filter
Expert:  Jason replied 1 month ago.

Have you ever personally seen the motor run correctly?

Customer: replied 1 month ago.
My name is ***** ***** Jason I've seen the boat motor running correctly
Expert:  Jason replied 1 month ago.

Hi Dan,

Got it. When was the last time it made full power without stalling?

Customer: replied 1 month ago.
Jason , last week while fishing , trying to fish yesterday . No luck !!! Boat stalls !Dan
Expert:  Jason replied 1 month ago.

Stalling at high speeds indicates the engine is simply running out of fuel. That can happen for 3 reasons.

1. There is some kind of blockage or restriction in the boats fuel tank and related plumbing. This can be anything from collapsing fuel lines, to crap in the tank, to a plugged up vent, or a bad antisiphon valve if the tank has one.

2. A weak fuel pump

3. Dirty carb

What we would do in the shop is first get a portable fuel tank and hook that up to the engine, and run It on that. If the stalling stops, then you know the problem is within the boats fuel tank and related plumbing, and that will need to be gone through in order to figure out why fuel isn't leaving the tank. If there is no change, then we would hook up a fuel pressure gauge on the output side of the carb, and run the boat as fast as it will go. Fuel pressure needs to be 3 to 7 psi at all times. This is a simple pass or fail test. If it's low, 99% of the time that means the fuel pump is bad. However, the fuel pumps do work off of crankcase pressures, and if compression is also low on the cylinder that drives the pump that can cause the pump not to deliver enough fuel. So if fuel pressure does end up being low, compression test the engine first before buying a new fuel pump. Compression pressures on something like this should be about 85 psi or better. If it is, then you can go ahead and get a new fuel pump. If during testing fuel pressure is good, and at least 3 psi when the engine stalls, then the problem is going to be in the carbs, and they are going to be dirty and not flowing enough fuel to sustain high rpm. Does that all make sense.

Expert:  Jason replied 1 month ago.

I think that should do it but I work for tips so I do want to make sure you are happy with my service before you go. If you had a further question on the issue by all means feel free to ask. If not, Just in case you do not understand the way the website works (and some folks do not). You do have to put forth a positive rating in order for it to credit me for helping you. When ratings are not done, the website simply keeps your deposit and they will not credit me. The ratings box is located at the top of the screen. To rate, you must select the star you wish and also confirm it. Please let me know if you run into any problems or errors when trying to do it. If you do have a problem, or if you can not see the ratings box which is at the top of the screen. Please reply back "I rate Jason's service _______" and fill in the blank.

Questions do not close out, so if you have to come back later on with follow up questions to the issue you still can even after doing a rating.

Thank you
Jason

Expert:  Jason replied 1 month ago.

I think that should do it but I work for tips so I do want to make sure you are happy with my service before you go. If you had a further question on the issue by all means feel free to ask. If not, Just in case you do not understand the way the website works (and some folks do not). You do have to put forth a positive rating in order for it to credit me for helping you. When ratings are not done, the website simply keeps your deposit and they will not credit me. The ratings box is located at the top of the screen. To rate, you must select the star you wish and also confirm it. Please let me know if you run into any problems or errors when trying to do it. If you do have a problem, or if you can not see the ratings box which is at the top of the screen. Please reply back "I rate Jason's service _______" and fill in the blank.

Questions do not close out, so if you have to come back later on with follow up questions to the issue you still can even after doing a rating.

Thank you
Jason

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