Just my .02 here, but I've also had this problem in the past. 1 1/2 on the needles and then fine tuning worked for me, although fatter on the low end does seem to help. One thing I read (even here on this site), and have tried with success to get a motor running is a couple of drops of low percent Nitro on the piston to give her a little more umph to fire.

thanks everyone for the advice.
still waiting for my new carb to come in post. i have had another go with the original brand new 813 carb and it still wont start but ends up flooding the motor on 1 turn out of the needles

at last got the new engine started,
new carburettor arrived yesterday (wt 257) bolted it on today and quarter turn of the engine and roar it started. FANTASTIC
no blisters no blood on clothes GREAT
the wt 813 is going back to bonzi if it economically worth posting it from n.e England UK that is
I would like to thank all of you that posted help to me on this great forum THANKS
off to the lake on Sunday to run it in

Very good news. Please let know how she runs.

will do, if it goes as good as it sounds we will be laughing

at last got the boat on the lake last Sunday. it runs very well for running in.
just had a little trouble with water getting in side the hull which i am sorting out now ready for next Sunday
can wait :=D

Excellent! :good:

Sorry for hi-Jacking your topic Lynny, but I had exactly this problem yesterday. I already have a 257 carb on my engine. And the engine was running in another boat last sunday, a week ago.

Put it in my thunderboat over the weekend and it won't start for the life of me.

I've pulled it out and checked the isolator block is flat (it's actually warped but i sanded it flat, while I wait for an aluminum version(It's the second time it's been sanded, it worked great the first time)), I've cleaned the carb out with contact ceaner, and I pulled the flywheel off last last night and the key looked still brand new.

I have noticed thta red coil looks closer to the flywheel than a business card thickness, what happens if it is too close?

The last thing you should know is thta the grey coil is different than the one it was running last weekend, each boat has it's own coil mounted in the boat. the problem with thta statement is that the coil in the thunderboat, where the engine won't start is brand new, never been run. the other thing is that there is also spark, but to my mind the spark looks weak and fuzzy? i.e a series of small spark rather than defined sparks.

It has occurred to me to put the coil from the other boat on which I'll do tonight.

Any other thoughts?

You're on the right track. If it ran in one boat and won't in the other, start by checking all the elements that changed from the switch. In your case, the coil seems like the most probable cause. I would be looking to confirm that the coil is properly grounded. The mounting hole with the metal insert in it must have a good path the ground (engine casing) otherwise you will have issues. You will also want to check all the gas lines and cell, since that most likely changed also. Confirm that the gas is fresh and good. As for the flywheel, theoretically, the closer (without rubbing) the better, but in all honesty, most of the time what I do it loosen the mounting screws and back out the coil as far as it will go, then tighten it down. Has always given more than enough spark strength and no worry about it rubbing on flywheel and robbing power. Keep us posted.