First off appreciate the time. now i know this question is broad because there are many factors to go into play but bear with me. i have a 99yr 200 hp yamaha vmax on a 20ft skeeter bass boat. now at top end speed i am only running 62 mph at 5600 rpms. and it will not go higher. now i know the prop is pitched correctly and it does have a jack plate which supposedly adjusted. i have smoothed the hull so no defects there. i have a hotfoot an not sure if that needs to be adjusted more. i have replaced all fuel pumps in the engine. only thing i noticed is at idle it not rough but it seems low as if it is uncomfortable and wants to be higher, so when a lil gas is given it seems to idle ok. it doesnt sputter or anything, but even at warm up sometimes it will cut off is gas is not applied. so should i adjust that higher. i have heard of also adjusting some screw for the oil or fuel intake and that might change it. any help appreciated. just list what you know to make the motor faster and ill figure out the rest.
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more speed? 99 yamaha 200 hp vmax
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if it used to idle well and now it does not its broke, fix it.
most likly needs a carb job.
if its a two stroke then at 5600 your already overspeeding the engine.
a model number would be nice as there were about 5 versions of a 200 HP yamaha in 1999.
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yours is a VX200.
max RPM for the VX200 is 5500.
try to use the largest prop you can to get the max RPM down to about 5300-5400.
then make sure ALL service items and rail pressures are correct.
make sure engine mounting height is correct.
your describing an engine with a running issue.
the VX motor does NOT use CCS and runs on all 6 cylinders all the time.
you may need a professional factory trained tech to inspect your engine.
once setup correctly an EFI engine NEVER needs adjustment and will run correctly until something breaks.
if it once idled correctly and now it does not then something broke or clogged.
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