Blaster WB1, tuning rebuilt carb. Now it won't start at all.

[swapmeet]

Ok, hope ya'll can help. I got some advise from members on the rebuild (jets etc).

I rebuilt the carb, used the Mikuni Kit, used the # of turns suggested by the members as well as the jet sizes. I've learned a lot about the different circuits in the SBN44 throughout this process, but now I have a problem that is beyond me.

Just a re-cap:
95 WB1,
ProTec Pipe, K&N Flame arrestor, WaveRaider Waterbox (not that it changes much)

Rebuilt the carb with the Mikuni kit, and replaced the jets as follows.
Pilot: 120
Main: 144
I forgot to order Needle & Seat, so I reused the factory one after cleaning and inspecting. I'm assuming its a 1.5, and used a new shiny spring, 65 gram I believe.
Also replaced all the fuel lines, and put in a much bigger cooling line (see: Pisser)

Went to the lake, got it to idle. Went to ride. The reason for the rebuild was the ski was loading up at half throttle. Knowing what I know now, it sounds like it wouldnt make the transision from the pilot to the main jet. When I went riding yesterday, it still exibited the same issue to some degree. I tried tuning around it, adjusting the low speed screw etc. Probably normal for the DIY crowd, it was ride, adjust, repeat.
The last time I rode it yesterday, it stalled out and died. I had to swim it back a short distance. I hasn't started since then... won't even try to start.

Here are the symptoms I can see. When pulling the plugs and cranking, there isn't much gas mist etc shooting from the plug holes, I would say there is none. So... No gas. But why?
My new hose is transparent. After cranking for a short period, you see bubbles come back out from the fuel inlet port. While cranking, there are air bubbles coming from the fuel return line, and the bubbles mentioned above disappear and get 'sucked' into the fuel inlet. So it seems like I have fuel pumping in. I tried new plugs for chits and giggles.. no help.

Do you think something went awry with my re-build? I'm still learning about pop off pressure etc, does this sound like a pop off issue?

I really hope ya'll can help. This is my wifes ski that she hasn't gotten to ride yet, and I told her she'd probably get to ride it yesterday. I'm tempted to just take it to the local ski shop and get bent over on diagnostics and repair. But i'd much rather learn and repair myself.

Sincerely :banghead:

 

[orangefinger]

ran mine with single 44SBN

Main 140
Pilot 120
N/S 1.5
95 G Spring
High Screw 1.25
Low Screw 1

 

[swapmeet]

So you're spring is different.
And you're main is a smidge bigger.

I forgot to mention, the jets I replaced were 115 pilot and 135 main.
Do you think the 144 is to big?

 

[ajmps1]

you should call protec

 

[swapmeet]

Good call. Called them, they said if it has too big of a prop on it, it won't get enough rpms.
I assume the lack of RPM won't allow the carb to switch to the main jet circuit?

So here's the $50,000 question. How do I tell if my prop is too big?

 

[blaster800]

where are you located ?

 

[tom21]

sending pm. too much to type. call me ya newb!

 

[swapmeet]

Not ignoring you Tom, just had a super busy week/weekend.

I'll give you a call this week.

 

[swapmeet]

Ok, so I have my carb set up per protec's suggestion

120 pilot
135 main
2.3 N/S
65g spring
1.5 low
2 high

I made my own popoff tester today, my Mikuni guide says I should be getting 15psi, but its popping off at 18. Not sure if that makes much difference, but I tried slightly bending the arm and the needle would get stuck once it popped off (at 15...) I've read conflicting info on cutting the springs and decided to just leave it at 118 and see how it does.

Going to the lake tomorrow, i'll let you know how it goes.

 

[4iflounder]

I had to turn my low screw in to .75 out. It runs great though!!! Good luck... Enjoy it

 

[swapmeet]

I'm not sure if i mentioned it in this thread, but when i took apart the carb afer my inital issue of it not running, the spring had come off the keeper on the arm. So it was applying more pressure on the N/S not allowing it to open.

i do not have a primer on this boat yet, so i put fuel in a squirt bottle and shot it down into the carb. Defintely made it easier on the intial start up.

 

[blaster800]

ok, so i have my carb set up per protec's suggestion

120 pilot
135 main
2.3 n/s
65g spring
1.5 low
2 high

i made my own popoff tester today, my mikuni guide says i should be getting 115, but its popping off at 118. Not sure if that makes much difference, but i tried slightly bending the arm and the needle would get stuck once it popped off (at 115...) i've read conflicting info on cutting the springs and decided to just leave it at 118 and see how it does.

Going to the lake tomorrow, i'll let you know how it goes.

118 what ?

 

[swapmeet]

118 what ?

I've got too much going on, I meant to say 15 & 18psi. Sorry, i fixed my post.

So I went riding today. Ski runs, but the problem that i was having in the first place is still happening.
I guess i'll transistion this thread into that problem?


Basicly, it feels like the carb won't consistently transistion into the main jet, it loads up very badly. I give it up to half throttle everything seems to run fine. If I give it more than that, it loads up.
If I play with the throttle it will make the transistion, and the thing flys, runs like a champ!... But here is the curious part, at least for me. After riding at basicly 3/4-full throttle for 5+ min it won't transistion at all. So I assume its something that might be effected by heat...? Seems like this symptom takes away the possibility that its the prop being too large.

This loading problem is why I rebuilt the carb in the first place... so its frustrating to have it persist even after spending the time and money on carb parts.

A guy at the lake today suggested that the needle might be sticking, and not completely returning down into the seat. That seems to makes some sense, but I haven't had time to look yet. He said that even a brand new needle and seat can get rough edges on the mating surfaces, causing them to stick. When I tested for pop off pressure the needle did get lodged in the seat housing after I attempted to bend the arm to allow it to release at 15psi.

The other suggestion was a possible broken reed... I have no idea if thats plausible or not.

So does this make any sense to anyone?

 

[swapmeet]

One other thing, the loading symptom was exactly the same with the heavily worn 1.5 N/S that I removed. So while the sticking N/S theory makes sense, I would assume that a brand new one of the proper size would yield an improvement.

 

[swapmeet]

bump