Blaster running poor, tried about EVERYTHING????

In the begining of the season my blaster was running poor( bogging on takeoff,sounded like a rev limiter but then would wake up but lose power off and on). Now it does about the same thing,you can rev it on the trailer a few times and it sounds good but all of a sudden it backfires and breaks up and takes longer to gain rpms then all of a sudden it revs normal once or twice then back to breaking up and backfiring. When it is in the water it will idle fine but when you hit the throttle it bogs or cuts out and has a lack of power. I have tried a different long block motor, 2 stators, 3 CDI boxes, 2 carbs,and 2 coils but no difference. I have also disconnected the kill switch but no difference,as well as a couple different plug caps and 3 sets of new plugs. After riding it,the plugs look good. This Blaster ran good last year but not this year. I have pretty much ruled out carb issues because I took the carb and threw it on my 61X Superjet and it ran perfect,and swapped the Superjut carb onto the Blaster and it didn't make a difference. I'm at a loss as to what else it could be.
 
have you tried different reeds ? '' its just an idea '' you made no mention of inspecting them

he said it does it with a different long block. id take that to mean he has tried new reeds. even if he moved the reeds from one engine to another, id hope he wouldve inspected them. it does sound like it could be bad reeds, though.

are your fuel lines and on/res valve clear? have you made sure that there are no breaks in the fuel pickup tubes inside the tank?
 
have you tried different reeds ? '' its just an idea '' you made no mention of inspecting them

The 2 different motors ran the same,and both had different sets of reeds,so i'm thinking it might be something else. Keep the suggestions comming because I have about reached the end of things I can try, and these suggestions are very helpfull and appreciated.
 
he said it does it with a different long block. id take that to mean he has tried new reeds. even if he moved the reeds from one engine to another, id hope he wouldve inspected them. it does sound like it could be bad reeds, though.

are your fuel lines and on/res valve clear? have you made sure that there are no breaks in the fuel pickup tubes inside the tank?

I'm going to pull the fuel pick up and look at it my next day off. I'm almost leaning towards some sort of fuel issue other than carb. I did notice that when I pulled the carb off my superjet(also 61x) that ran perfect to swap it unto the Blaster there was pressure in the fuel line,but the blaster had no pressure. I did inspect the pulse line and it was good.I haven't seen a leak aywhere,so I think the lines are good(they look good) and I have tried switching the petcock from on to res,and had the tank topped off.
 
Still can't figure this thing out. I pulled the motor and resealed it with Yamaha crank seals and gaskets. I haven't tried it in the water yet but it starts and idles great,but as soon as you hit the out of water rev limiter it backfires spiuts and breaks up so bad it blows off the water box boot. Anyone that can solve this problem I'll paypal $50 It has 150/150 compression and is all stock.
 

tom21

havin fun
Location
clearwater FL
bad fuel, water in fuel, pickup tube clogged broken or missing, bad fuel switch? you tried everything else but didnt mention what you found on this.
 

Dustin Mustangs

uʍop ǝpıs dn
Location
Holland, MI
restricted exhaust ?

^^This is my guess.^^

You could run a fresh piece of fuel line from a source of known good gas straight to the carb. No filters, no pickup, no valves, ect; just stick the new line in some fuel. Start it up on the trailer a few times like this to get rid of the old gas still in the carb. Then put in new plugs and see if it acts like before.
 
It ran great in the water after resealing it,so at this point I assume it was the crank seals as they felt pretty loose on the crank. It still backfires when it hits the out of water rev limiter on the trailer but ran great for the 1/2 hour I just got to ride it. Maybe it is easir to hear the backfire through the aftermarket water box,because I can't hear any backfiring when my superjet is hitting the limiter. When I pulled it from the water and started it to clear the water box,it sounded great for about 10-15 seconds then started the backfire sound again but there was no more water comming out so I shut it down. I'm going to assume its fixed at this point,but the backfire still bothers me a little.
 
Had this problem 2 years ago on our Blaster. Tried to cut back the wires and put New plug boots on but in the end fixed it with a JSS wired coil and havn't had the problem since. You say you used 2 dif coils but are they both old used ones?
 

Matt_E

steals hub caps from cars
Site Supporter
Location
at peace
Is your fuel tank holding pressure? Ride it and pull of your gas cap and see if the tank has pressure if not the vint is bad. Just a thought.


The check valve is supposed to let air into the tank but not out.
The fuel system uses a suction hose. It doesn't need pressure inside the tank.
 
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