Please Help with 94 Blaster 1

[hooka-2]

I have a 94 blaster 1 with a 62T motor FFP mod pipe, no port work, and twin 38 mm Mukunis. I set the jets up like the Factory web site suggested. 140 on the main 70 on the low side and 115 gram springs, stock needle and seat. Engine is new rebuilt so I know it's tight. 155 lbs per cylinder. The problem is it has no low end power. It bogs badly and then it's like a light switch turning on when it hits. It runs fine if I keep the rpm up, but as soon as I let it get out of the power band it bogs again. The best i could get it to run was when I almost closed the the high speed needle ((1/2 to 3/4 out ) and had the low at 1 turn. The water screws on the pipe are set: front and middle closed, bottom open 3/4. Sorry about the long post, just trying to get the facts out. Any help would be appreciated. I'm thinking maybe smaller mains and lighter springs??????????

 

[robertg]

The Superjet likes a 75 pilot and 135 main so that might work for a Blaster too. You may want to try a 95g spring also. What type of flame arrestor are you using?

 

[extreemthrottle]

sounds to me like it needs to be fatter on the bottom. definatly use the 95 gram spring, and try the 75 L/s jet.. i'll get mine set on the bench before install and then when i take it to the water, i'll leave it on the trailer first, warm it up, make sure the pipe and or the head does'nt get to hot. then start to tweek it some on the trailer before i ride it and do final dial in on the carbs.. hope it helps..

 

[hooka-2]

I'm using vortex flame arrestors. I can never remember the color of the springs . What color are the 95 grams? I tried to set it up on the trailer and got good throttle response just off of idle but trying to hold maybe 2000 - 3000 rpm it ran real rough. Just didn't want to develope any power. I was kind of wondering about the pop off pressure. It seamed like it had to build up pressure (rpm) before it would hit and clear. What pop off should I be seeing?

 

[Fathom]

IIRC, silver.

 

[hooka-2]

Some one please translate into newby english. What is IIRC? I understand the silver part.

 

[Fathom]

If I Remember Correctly.:biggthumpup:

 

[hooka-2]

A little more info on this brain teaser. The ski had the same problem when I bought it. It had a 760 motor with a 46 mm single carb. The compression was low on one cylinder and the reed pedals were chipped so i thought that was the problem I replaced the motor with a newly rebuilt 701 and twin 38s. Same dam problem. It's better but I just can't get any low end power until about 3500 rpm and then it hits like a light switch and hauls butt. Could there be something wrong with the pipe or the ignition? I used the same 701 electrical system that was on the 760. Any ideas? this just doesn't make sense.

 

[superjetnfresno]

i was going to say ignition but u beat me to it

 

[yamahammer]

i dont know how long your pipe has been on, but when we put mine on (same mod pipe) we had bottom water screw about half way out and top screw cracked and it was a dog down low. shut off top screw completley and just cracked bottom screw and ski woke up and pulled harder down low and more rpm- we also then added jetworks valve later set pretty high to further dry out waterbox and bottom end picked up even more and pipe always still ran very cool- might give it a shot- way easier than pulling carbs- also shutting off top pipe screw helped with side mounting as water did not spray on exhaust ports when boat was ditched or leaned way over- just my personal observations- good luck!

 

[hooka-2]

Please keep the ideas coming guys. This thing has me baffled. I've only had this thing for a couple months and it hasn't been right since I've owned it. The pipe does run much cooler than it did when I got it because I added dual cooling. The guy I got it from tried to set up dual cooling and had the second cooling line coming off the bilge fitting on the pump. Talk about hot in a hurry. You could fry an egg on the water box and it still had no low end. Do the water setting on the pipe really make a dramatic difference? I set them to the factory reccommended setting for start up because everything else on this ski was wrong when I got it.

I've always been a Kawasaki guy and this is my first attempt at Yamaha. Hope it's not my last. I've never seen a ski react like this.

 

[yamahammer]

my boat sucked a$$ with fp settings- dry it out works much better- im not saying this is the exact cure on your boat, but it sure helped mine- similar setup , but 760- side note we did this to our standups and it rocked out on those boats too- lots more rrrrrrrs on topend- has me looking at drypipes- ive no experience with them- but can always use more power and speed:woot:

 

[hooka-2]

I'll definetely try to dry it out a bit. The pipe is hot but does not sizzle at all the way it's set right now. Still searching for the pop off settings for this thing. Anyone have a clue what I should be seeing on twin 38's?

 

[hooka-2]

I've been told 20-21 on pop off. Anyone else want to chine in. What about jet sizes? When I got these carbs (used on a stock 1994 wave venture) the main jets were staggered. 120/130 Anyone using staggered jets on twin 38's? I can't imagine someone changing out one jet on a stock ski, so I'm assuming that it was a factory set up. Should I keep the stagger when I upsize for the pipe?