'02 Yami 50TLRA - no power under load

[vin]

Hi All -

Long story short, she purrs like a kitten at idle, but won't get above 1500-2000 under load as it "bogs down". Things recently checked & work performed: compression (good), spark (good), carbs (all 3 cleaned/rebuilt), fuel pump (new), fuel filter (new), fuel (good, clean), primer bulb (new), fuel line connectors (new), fuel tank pickup (good). Could this be a prime start system issue (stuck in open position)?

Thanks for your time!

 

[SKE60]

Re: '02 Yami 50TLRA - no power under load

Had a somewhat simmilar problem with my 99 Yamaha C60tlrx, but didnt do it all the time. Finally figured out overheat alarm wasn't working so got me thinking maybe running hot and first replaced thermostat, didn't change anything so then replaced inpeller, took out yesterday and finally runs like its supposed to. Mine would usually bog at about 2000 rpm after idleing or trolling .

 

[99yam40]

Re: '02 Yami 50TLRA - no power under load

It is easier and cheaper to test things instead of just replacing parts and hoping it fixes the problem

Like SKE60 talked about, check the alarm system to make sure it is functioning properly.
Check timing
If it is in safe mode the timing will not advance to where it needs to be, thus limiting RPM.
find out what will bring in the alarm and put motor into safe mode. Temperature and maybe oil.

If all that is Ok then check the fuel system pressure and vacuum to see if there is a problem and go through the carbs again if no other problem is found.
​

You can check the diaphragm in the Prime Start system for tears and switch to off position to eliminate that system. You can test the heater on the system like the manual says to make sure it is doing it's job, but that system if for start and warm up and if you do not have a problem then I do not think it is a problem