If this is your first visit, be sure to
check out the FAQ by clicking the
link above. You may have to register
before you can post: click the register link above to proceed. To start viewing messages,
select the forum that you want to visit from the selection below.
Have 86 Yamaha 150 and suddenly loss about 40% of power. Still ran and started without missing out but with power loss. Check fuel filters and all OK. Any suggestions where to look.
Thanks
Bigdaddy - I think the first thing I would check is the compression - you could have a couple of cylinders that have gotten weak.
If compression checks out ok, then start with fuel. If your motor has been allowed to set up for more than a month w/o being run (and you did not "winterize" it per the owner's manual) then the carbs could be clogged with gum/varnish.
First try a shock treatment with SeaFoam or RingFree. If that does not do it, then pull the jets and squirt some Berryman's Chemtool into the orifices. If that doesn't help, then tear down carbs, clean, and install a carb kit.
Check the ignition advance linkage from the throttle to the pulser coil assembly - maybe something is amiss there.
Also, if that fuel pump is more than five years old, replace it.
Good luck [img]smile.gif[/img] ,
Ken K
Comment