2001 90 HP ELPTO Mercury 2 stroke outboard bogging down

[Hjerome50]

Good evening everyone, I’m having an awful time troubleshooting my 2001 90 HP Merc outboard bogging down under load. I’m stumped. Typical to other posts I’ve read the engine revs fine on Muffs but once it’s under load the problem persists. I’ve done the following and have the same problem:

- run on a side tank
- rebuild all 3 carbs with OEM kit
- rebuild fuel pump with OEM kit
- change all spark plugs

what’s next?? Does anyone have any ideas?

thanks for the help!

 

[mav6759]

I got the same motor, had the same problem, had to clean my carb's 5 times before they acted right. Try cleaning the carbs again, this time really take everything apart. And make sure your floats are level, and needles are clean, go to the dollar store and pick up some air in the cans, blow out every passage, that you see. Leave no stone unturned. Use about 3 cans of carb cleaner and soke the carb's in seafoam for about 3hours or longer. These carbs from what I understand are hard to clean.

 

[Texasmark]

You missed the fuel filter. Quick check, remove it and attempt to blow air through it in the direction the arrow on the side indicates. If you feel any resistance to your blowing moderate forcefully (considering the hole is only 5/16") it's plugged. Cutting it open will tell you where to look.

Reasons are/can be 2 fold: Fuel line to the tank is full of tan crispy chips and or engine fuel lines are deteriorating and dropping little black specks of fuel line into the carbs, blocking the jets. BTDT on a 2002 at 10 yrs of age, ethanol E10 fuel.

Last if you didn't blow out your carbs with compressed air, including the high speed jet in the bottom of the bowl, really good, you may find a little piece of rubber blocking one or more of them. BTDT too

One would assume that things were working ok otherwise and just developed this problem and you didn't loose spark on one cylinder...check with a timing light is the easiest way and compare cylinder to cylinder results, or do a spark gap test as many folks do.