Invader losing power? Bogging

[Tin-man]

I have a 79 440 invader.

Need some help. The sled starts and idles fine. When I start moving, and give it full throttle, it will go to full throttle for about 3 seconds, then lose power. Its like there isn't enough fuel getting into the machine. All through the throttle range, there is not power. It is bogging.

I am sure it is a fuel system issue.

The sled has new crank seals, rebuilt carbs, and new fuel lines. New fuel filter too. I have not done anything with the fuel pump. The plugs are not fowled.

I am thinking fuel pump. What are your thoughts?

[Lloyd (ljm)]

Hey Dustin

 Check your plugs.

 Are they tan, brown or black?


 Lloyd

[jimvw57]

float set too low? maybe a plugged jet. I usually replace them.

Carbs balanced?

[Checkmarks]

Start, idle, and WOT.  Shut down when the problem occurs.  Disassemble the carburetors carefully and see if they have fuel in them. 

With ONLY float bowls full I would bet you could go 30 seconds before the machine shuts down from lack of fuel.  Unlikely the pump if the sled idles fine for say 30 minutes.  You have drafted the idea the pump could be bad.  Any Mikuni pump will get the job done, slap on a known good one.  Gravity feed the carburetors bypassing the pump all together.

With Lloyd on this one, what did your plugs say?  Was one of the cylinder exhaust manifold sides cold?

[Interceptor398]

Check the gas line in the tank and make the tank has only gas in it.  When I first got my 81 Invader I had the carbs off 3 times before the crap from the fuel system got cleaned out.