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Jason, Marine Mechanic
Category: Boat
Satisfied Customers: 15685
Experience:  Degree in Marine Technology. Gas and diesel marine mechanic.
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My boat drives great for a period of time, then at some

Customer Question

My boat drives great for a period of time, then at some point it seems to choke out at high speed...I can drive it with low rpms. If I raise the motor cover, drive in low speed for 8-10 minutes it will run good again. Sometimes I can feather the speed up, and it will get more rpms when running sluggish. ????
JA: Sometimes boat issues seem like they'll be really complicated, but end up being easy to fix. The Marine Mechanic I'm going to connect you with knows all the tricks and shortcuts. What confuses you?
Customer: Sometimes it might run great for 2 hours before it starts to run sluggish at higher rpms...
JA: Is there anything else important you think the Marine Mechanic should know?
Customer: Nope...that is the question
Submitted: 11 months ago.
Category: Boat
Expert:  Jason replied 11 months ago.

Hi Frank, my name is Jason.

Which engine is in the boat?

Have you ever personally need it run correctly?

Customer: replied 11 months ago.
Jason, it is a mercruiser on a 98 Chaparral. It ran correctly until last summer. It has been doing this since then. I have had a couple of mechanics who changed the fuel filter; one changed the "rotor"; but nothing seems to help.It always will run good to begin with. After a period of time, 20 mins to 2 hours, it will become sluggish and start skipping at higher rpms. If I give it all the gas, it will choke out; but I can run it at low rpms and it runs okay, though you can hear that the engine is not running smooth. If I park the boat awhile, it starts and runs good again. I can open the engine hood, drive it at low rpm for awhile, and then can feather it up to higher rpms; and sometimes it takes off and runs great again.
Customer: replied 11 months ago.
A shade tree mechanic told me today it might be a "shirt interrupter switch"......
Expert:  Jason replied 11 months ago.

Got it. Mercruisers are cataloged by serial number. Can I get the serial number on the engine so I can run it and see exactly that you have.

Expert:  Jason replied 11 months ago.

Did you have the serial number Frank?

Customer: replied 11 months ago.
0L 051790 I am not sure if the 0's are numbers or letters. I believe they are numbers.Frank
Expert:  Jason replied 11 months ago.

It's not a shift interrupt switch problem. Either the ignition system is breaking down because of a bad ignition coil. Or, the engine is starving for fuel because of a fuel tank issue. What we would do in the shop if you brought the boat to us is we would take our own 5 gallon portable fuel tank (complete with hose) with us on the boat. We would run the boat until we could duplicate the problem. Once it's running poorly we would hook up the portable tank to the fuel pump and see if it runs better or not. this is a simple pass fail test, and it either will or will not run better on the portable tank. If it does, then the boats fuel tank and related fittings and lines has some sort of blockage in it that will need to be found. If there is no change, then the problem is the ignition system breaking down, and we would replace the ignition coil. Does that all make sense.

I don't know how you want to leave this but that is where you stand on your end and what needs to be checked. 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

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