Rebuilt a Dumas Scarab 40" deep-v with a Zenoah 260 (previously ran as nitro). Been unsuccessfully running it with a Futaba 2 PL FM radio. The longest I've had it run in the water is 2-3 minutes. Problem is everytime time it gets about 200 feet away (sometimes less), it stalls (it runs fine on a water hose). The last time I ran it I noticed that the servos were glitching pretty bad as I swam out to retrieve it. This continued until I got within 50 feet of the radio. I have a feeling it's the radio but the kid at the local hobby shop said some glitching is normal and that I need to take a closer look at the engine and get a digital servo. Bought the servo, no difference. The failsafe kicks in at 10 feet with the antenna down. That's not normal right? I've tried a different receiver, different servos, w/ and w/o the failsafe without any difference. Any suggestions? I've tried adjusting the settings on the carbs, no diference in stalling, just in performance before it stalls. Thanks

Not sure but it could be a problem with a connection in the transmitter to the antenna
or something?
I run a SANWA MX3 FM and dont have any problems at all, so dont race out and spend a fortune on a 2.4 system which is all they try to sell you now days!
If your dealing with a kid at the hobby shop I would switch hobby shops!
Theres nothing like years of experience to help you out, and most older guys running shops are always glad to find the problem and help you fix it!
There are a lot of shops popping up now but the young guys are all plug n play!
They have never really pulled anything apart to try to fix things!

Thanks for the advice. I'll contact Futaba and see if they can help. I've had the radio for less than a year so it should still be under warranty. Thanks again. I'll f/u in the future when this is resolved.

Hi
First up do some testing on dry land
If you can get someone to help by standing near the boat and watching the servos makes it easier,with the tx aerial up walk away from the boat (motor not running) working the controls as you go.see how far away can get.
If its only 20 to 50 feet check the RX aerial isnt broken or has been cut ,batts are fully charged and giving out correct voltage,tx batts are fully charged if you can try to borrow another TX I have seen a faulty TX cause issues out of teh box.If you can walk far enough away you cant see the boat then try with the motor running, blip the throttle as you walk away if it starts to play up,check that you have the correct type (resistor) spark plug,check the plug gap,check that the flywheel isnt hitting on the coil pickups,check for any metal to metal joints that might be rattling things like rudder push rod connection at rudder(this can cause RF interference) .If that all checks out and it only plays up on the water then check where the rx aerial is in relation to the water surface get it up as high as you can,Ive never heard of FM having issues like the early spectrum 2.4 dsm1 radios but you never know.
cheers
Wozza
Ps I also forgot if your radio system runs xtals check they are not loose or damaged,mainly in the RX. I always put some tape over mine as I had one fall out in a nitro heli once the end result wasnt pretty lol

As talked about on another thread .... engine NEEDS to have a resistor "R" plug installed so it creates no RF interference.

I'm sorry to hearing about problem with FM radio,
but I want to say, that main problem in cheapest radio kit, 2PL FM is better for ground toys and auto. Not for gas boats.
It have not any advanced settings and trimmers, easyest electronics.

Please check:
TX antenna must be screwed-in with garantee. (I met a same problem also not far. my friend with much better radio thinking about everything but not about TX antenna. he spent a nervos day, it was look not funny)
No any rest water in the RX body, and servo box!
Fresh, charged battery with 5 cells.
Well-working power switch or jamper.
Antenna must be stay and fixed as far as possible from coil wire.

good luck!