1979 JOHNSON 175HP OB

[BUSHMANKEV]

HELP I HAVE A 1979 JOHNSON 175 HP OUTBOARD ON A '79 17 FT. MONARCH. ENGINE RUNS GREAT AT IDLE AND TOP END BUT CUTS OUT AND DIES AT LAUNCH UNDER A LOAD ABOUT 50% OF THE TIME. I CAN GET IT TO PLANE OUT AND RUN FINE IF I HOLD IN THE CHOKE WHEN IT STARTS TO CUT OUT. MY MECHANIC HAS TRIED EVERYTHING...REBUILT CARBS, PLACED ON DYNO, NEW LARGER FUEL LINES, CLEANED FUEL TANK AND FILTERS, NEW PLUGS AND CALIBRATED JETS AND THROTTLE. BUT NO LUCK, STILL ACTS UP. ANY INSIGHT. THANKS.

 

[Hooty]

Re: 1979 JOHNSON 175HP OB

Well, it sure sounds like the problem is fuel related. Next time it starts cutting out, instead of applying the choke, pump the bulb. You may have a fuel pump problem. Keep us posted.<br /><br />c/6<br /><br />Hooty

 

[ob]

Re: 1979 JOHNSON 175HP OB

Bushmankev,If you are just experiencing this cut out and die problem when throttling up from idle and your midrange and top end performance is fine I'm leaning more toward mixture setting being too lean or the carb linkage is not synchronized properly with ignition timer base.This out of hole from idle situation on two stroke outboards is a critical point which will challenge the idle mix and synchronization of carb linkage if it is not set precisely.However, there could be one way that fuel delivery(fuel pump) would be inadequate at a throttle up from idle situation and that is if the crankcase pulse hose that drives fuel pump air motor was not sealed.Also ,do a visual on timer plate with motor cover off.With engine not running move the throttle control into forward at full throttle position and insure timer plate will advance all the way to the stop screw and is not sticking.You may have to have an assistant spin prop in forward rotation while shifting into forward so shift linkage doesn't bind.<br /> This is all under the assumption that your carbs were overhauled properly and there are no restrictions in idle jets or porting.