1986 Force 125 shutting down after throttling to get on plane

[jscottt]

I have a 21' bayliner trophy with twin 125 forces. Both motors ran well last year. This year one motor began to cut in and out while motoring on the first trip. Got it home and ran it in the driveway and everything seemed fine. Took it out the next week and got out of the harbor with not problem. As soon as I get the boat on plane, the engine backed right down and stalled. Any help on why everyting seems fine in the driveway, but when trying to throttle this motor to get on plane, it would cut out?

 

[12Footer]

Re: 1986 Force 125 shutting down after throttling to get on plane

It sounds like fuel pump, water in tank and bowls, or tank vent plugged.<br /><br />If the fuel pump has not been rebuilt in the last 3 years, it may be the culprit. The diaphrams slowly desolve in today's ethanol or alcohol-'enhanced' gas.<br /><br />place a spray paint can (or simular small container) lid under the bottom carb, and crack the bowl retainer screw. If you have any water in the fuel, check the others, all filters in line, and fuel tanks for water.<br />The best way to check the tank vents is to check the primer bulb. If it colapses underway, it's a good bet the vent doesn't vent the tank, or there is a restriction in the fuel line or pickup tube in the tank. Unscrew the gas cap a little bit while underway, and see if performance improves. If it does, it's not an obstructed fuel line. It's the vent. Mud dawbers and some other members of the wasp family love the smell of gas for some very odd reason, and will seek-out your tank vents, carbs, fuel lines, exaust ports etc, to built thier nests in.<br />Don't laugh. It's happened to me many times, in marine and auto engines, and lawn gear stowed inside my garage...But then, I live in Florida (bug world,USA).

 

[jscottt]

Re: 1986 Force 125 shutting down after throttling to get on plane

Thank-you 12Footer. The primer bulb to that engine does stay collasped for 10 or 15 seconds. I've noticed this all along, but it never dawned on me that could be the problem. I will begin investigating the vent or a fuel line restriction. I don't have water in the bowls and a fuel pump rebuild kit was added last year. This really helps, I appreciate the advice. I will post my findings.

 

[jscottt]

Re: 1986 Force 125 shutting down after throttling to get on plane

Frustrated over this one <br />The oil resitant fuel lines that run from the inline filter to the engine were the culprits. Its hard to explain but I'll try anyway. Its almost like internal blistering happened in the fuel line. It got to the point where hardly any fuel was getting through. Any ideas on how this could happen. <br />Thank-you for the help 12footer, I can boat in confidence once more