loss of power at full speed

ive got a 1994 75 hp mercury tiller motor was running great and was heading back to the launch and had motor running wide open and it seemed to cut in and out when running full speed and is kinda intermittent runs fine then cuts out and back to full speed and was trying to get an idea of what the problem may be .... replaced the plugs and fuel filter and still have the problem.. carbs?

Re: loss of power at full speed

same hapends to mine mate........i have a 60hp mariner 1987 and it does the same....been doing it for a year now, could be switch box....

Re: loss of power at full speed

If you can reduce the throttle and it cleans up immediately, then I wouldn't suspect anything electrical/electronic. I would chase fuel.....I have had engines outrun their fuel source with the problem being the fuel source/external lines/installation/tank venting/kinked delivery line/goo in the line from using water eliminator (alcohol) in the tank on built in tanks/bad squeeze bulb sort of things.

What I would do would be to squeeze the bulb on the fuel line the minute it starts to drop off. If things improved, might be any one of the things mentioned above.....BTDT over the years.

My experience with electronics is that they cannot recover that fast if they are failing....a thermal problem they can have, but it takes time for it to develop and time to correct...if it will...BTDT too.

HTH,

Mark

Re: loss of power at full speed

thanks for your input i do use marine stabil and have used the quicksilver fuel treatment for ethanol.. i will try to replace the bulb im sure it is old and do you recomend running sea foam through also to cledan up some of that goo