Just about to give ..

[jasperastro]

Have 1978 85 hp, Javelin , <br />Motor runs fine for first few minutes, runs real well.Full throttle, half and idle.<br />After that motor boggs out,while trying to accelerate to more than half throttle. Motor bucks alittle, but wont go more than half throttle. Idle is just fine, i stop the boat and pull up throttle to high idle and it does fine. Put it in gear and accelerate and it boggs out.<br />Cleaned carbs and pots, New plugs, new fuel in clean tank, inline filter installed, changed suspected bad coil, thought that was problem....not....good spark on all plugs and compression at 115,115,110,105. <br />Cant figure this out, what else can i check?<br />Engine runs like a spotted ape at start, then wont go beyond half throttle after about 10 minutes, you can go into it slowly or hammer on it, still same result.<br />Motor does not run hot, impellar good shape, good circulation.<br />A friend of mine had same problem, said it was the limit switch, would this be the culprit?<br />Dont want to mess with it untill i get some advice<br />Maybe something simple. Help.....jas......

 

[R.Johnson]

Re: Just about to give ..

There is no such thing on your engine as a limit switch. This sounds like a fuel restriction. If your not already doing so, run the engine on a 6 gal. tank. I've see primer bulbs act like that if a check valve comes apart. If you are running on a built in tank, check the anti-siphon valve in the tank. Also check for an air leak somewhere in the line.

 

[jasperastro]

Re: Just about to give ..

Thank you for your reply.<br />I have a built in tank, where would the anti siphon valve be? <br />I put a inline filter between the bulb and the tank, thinking this would eliminate the chance of trash getting to the carbs.<br />Like i mentioned before the motor runs fine for a little bit, then seems to be starving for fuel,the inline filter is showing a ample supply of fuel going through, connections are tight, with a small bubble. Had this power problem before the inline was installed. It only happens when in gear and trying to get up to plane speed. Otherwise idling and raising the throttle arm it does just fine.<br />Maybe it would be best to remove that old tank...plastic....and replace with two 6-gallon tanks. <br />I cleaned it out, but it is old, original tank that came with boat. 1982 Kingfisher bass boat. Thanks for your interest, i have been fighting this for a while now. ....jas....

 

[rickdb1boat]

Re: Just about to give ..

Like R.Johnson said, get yourself a new portable 6 Gal. tank and fittings, New fuel line and bulb and see if that solves your problem. That eliminates the anti-syphon valve problem, water in the tank, stopped up fuel pick-up, Clogged Vent, Air leaks in the old lines and numerous other problems related to the fuel system, all in one feld swoop. Let us know how it goes...

 

[rodbolt]

Re: Just about to give ..

hello<br /> do all of the above and drain and flush your carbs again.<br /> once any trash or water gets in it cannot get out and will float about and do funny things.other than that its time for a test wheel or a dyno and some dymanic trouble shooting.<br />good luck and keep posting<br /> but it does sound a bit like a fuel problem.

 

[jasperastro]

Re: Just about to give ..

Thanks for the info, I will purchase a new tank and fuel line and see what happens.<br />I will leave the old tank in just incase this is not the problem.<br />I sure do appreciate the help and i will give you all an update soon. <br />Lets hope this will finally cure my dilema.