DRAGONFIRE81M

ok after fixing the tank on the nitro jet vee . im still having a problem with it die mostly on the upper end of the rpm . it will run some times on the low end some times it will stall out 5' from takeing off but i thank that has to do with the upper end to . i even tock the tune pipe off and ran my buggy pipe to see if i didnt have the presser fitting in the right spot . still did the same thing . when im running at half trottle it does pretty good but if i give it more it starts cutting out almost like it running lean . i know the fuel system is clean and im starting out at 3 turn out on the carb . also if i dont idea it up before i prim the pump it will stall out im thanking larger flywheel for that im only useing a hpi savage with a 5mm-.150 ose cable cupler . any thought would be great thanks

Dan S

Have you tried more than 3 turns out on the HSN?

still sounds like its starving for fuel for the top end, try it and check all you fuel line for any pin hole as well.

Dan.

DRAGONFIRE81M

yes i startat three and i went two 4 1/2 . i even removed the niddle to make sure there was no trash . and even blow throw the presser line " not running" and blepped the trottle and i was getting fuel . ill check my lines but i thank there all good they are new line to add . this is with a clutch set up when i found out it had a leaking tank http://www.youtube.com/watch?v=sYeKM-UPi7w but it does the same thing just not as bad

Dan S

so what happened when you went to 4 1/2 turn?

I know the video is not the best quality but I can't seem to see any smoke.

what is the engine?

Dan.

misshydro

Hay try to take the carb off and take it apart and clean it out with carb cleaner. You might have somthing obstructing the hight speed needle area? Still sounds like your still on the lean side? I know when my CMB.21 dose that,when I'm trying to go faster and wants to die out/bog on me. So I turn mine out to 1/2 and she goes.

DRAGONFIRE81M

like i said that video was when it had a leaking tank. know that is fixed it does smoke like it should . could it do this if its to fat . its a ofna .26 that i put a go engine water jacket on . i have another one of these motors and a .32 on my buggys and they run great there i ordered a .21 flywheel today . but ill run it some today . but i cant get any video my cam was stollen monday . [:@] thanks guys for the help

misshydro

Ok that might help me understand maybe better. It that a side slide carb your using??They can be very tricky to tune in. Be there are very responcive carbs/snappy responce.

DRAGONFIRE81M

yepo i tried to load some pics but it wasnt working .

misshydro

Try like I'd said clean it out.the carb. Had that happend to my vegas with a thundertigerpro.21 buggy BX-R motor. But there another proublem to. We seen guys running car/truck motors in there boat. These buggys motor might not work wright with out timming mods to these motor. Boat and buggies motor are timed differently. Boat motor are under alot more load then buggys motor=different timming curve. Rigger guys,some are using car motor and getting away without not much mods because there not much of a hull to these riggers=less weights=less loads=faster speeds. Oh!!! You might have to sorten that tune pipe. It might be to long too. Car motor like there tuns about7- 7 1/2 -8" long That might be part to most of your proublem too.On my thundertiger pro.21 BX-R the tune pipe is 7 1/2. Whats your tune pipe lenght on your boat??

DRAGONFIRE81M

ok after my last post i headed to the lake for some more test and tune . heres what i got .
first still running the buggy pipe i backed the niddle out 5 turns and started it up " this was with out doing anything but relubeing the flex cable " filled it up im running 20% at the moment cant get anything higher . ok i set it in the water and wow what a diffrence . but still no top end but it wasnt cutting out like before . so i had also cut down some props that was a 3 and 4 blade with less pitch then the stock 2 blade . heres what i got . one a little slower speed and i was hitting the top end but i was airating the impeller . about 1/2 trottle was it after that it just rev out . so that tells me some i need to tune my pipe for a little more upper end torq . to get the rpm up . what do you all thank .

misshydro

Ok hears form what I was told. shorter the tune pipe more topend rpms,but you can also lose the tork power too=have to run smaller props. Most guys on a marine motor at 9" and start cutting them down1/4 at a time until you find that sweet spot. Buggys some start at 8-8 1/2 then go from there.A 37mm prop might be a good starting point? The one prop that was asperating/cavating, sounds close,but you might need to bump up one prop bigger than that one,that might be your ticket prop. I'm running a X437/3 and man my boat moves faster,then my 40mm prop. The 437/3 is a 37.6mm prop size.

DRAGONFIRE81M

i cant change prop size only pitch and # of blades . " its a jet drive " the pipe is at 12 and 3/4 " its the 1120 mac oh yeah the impeller is a 29mm

misshydro

If your motor is a.26?? your tune pipe is to long. You have to start cutting it down a 1/4 at a time to find that sweet spot. The tune pipe is like a booster/blower,these motor act like a motor cross bike. all of them have a power band that kicks in at the wright rpms. The nitro boats are the same,they have a power band too. The key is to have the wright tune pipe and the wright lenght to have that power band. I'm going to give you three links to help you understand this better. here two are prop info and sizes.[link]http://rcprops.com/TechNotes/rcprop_tech_info.htm[/link][link]http://www.xtremercboats.com/tech/propchart.htm[/link] The other is tune pipe info.[link]http://www.prestwich.ndirect.co.uk/tunedpipetheory2.htm[/link] these should help you out.

DRAGONFIRE81M

thanks for the info . those are some pretty good sites

misshydro

I dont know much about jet drives, I dont know if theres much prop selections for them? If not I would think about converting ditching the jet drive for the adjustable strut out drive. Then you'll have a much better selections of props to try out. Or better yet use the SV27 stinger and drive parts to your boat. Since there both V/mono hulls.

DRAGONFIRE81M

sorry man not out for speed just 3" water running . theres nothing like doing up stream over rapides . if you check out the nitro vee forum i had it on the stock drive . and it was way to fast and ran really great on the stock drive line . if i wonted that crazy speed i would have went with your set up for better contral . but i didnt . anyway i was going the same speed as a .18 os in here on a 40mm prop at only 1/4 trottle if i gave it any more then that it was uncontralable the way it was . at the way its running now its in the ball park of 25-28 mph i know i can get it up to this just under this speed if i can get for rpm out of it . http://www.youtube.com/watch?v=hJNx468n45E thats the same drive but electric . and here is this boat stock with a os .18 http://www.youtube.com/watch?v=8M-0SBxqeOA