[ryan paul]

Hi .I have a rio.It fires on every pull but will not catch and run.Can you suggest a needle setting to start with.I believe i have tried everything but if your works please let me know.

Originally Posted by d_orgera

I purchased a Rio 51 when they had the big blowout a couple of months ago. Mine had several defects that needed to be fixed before I could even run the engine. The folks at Hobbico were nice enough to send replacement parts at no cost and no questions asked.

I first ran it in my back yard with the water pickup connected to my garden hose...ran a tank through it that day and adjusted the carb just enough that it wasn't stumbling and spewing. From the factory it was set way too rich. It's still on the rich side for the sake of breaking it in but it's idling well and transitions well.

Anyway, it ran great in my back yard for an hour, but won't stay running in the lake for very long. The problem is that after about 5 minutes (or less) of running in the lake at various speeds, it seems to overheat and die. When we retrieve the boat, it's always sizzling hot and smoking, then it won't restart until it's cooled right down. I keep checking to make sure the water uptake is clear. I lowered the water uptake tube as far down below the hull as it will go...from the factory it was level with the trim plates. I don't think it's circulating enough water to cool the engine, header and muffler. Is there an electric water pump available that can improve cooling?

Any other suggestions?

Should I be able to run for an entire tank or are these desinged for a few quick laps then cool-down period? I've got years of experience with RC gas aircraft engines, but this is my first gas boat.

Thanks
Den

[d_orgera]

Hello Ryan,

Well, the Rio 51 has certainly been a source of frustration for anyone who has owned one. It's a great performing hull but everything else, radio, engine, exhaust system, prop drive, etc, are all crap.

Per the designer's (Grimracer) suggestion, close both needles then open the low-speed needle 2 1/2 turns, and the high-speed needle 1 1/8 turns. I found the low-speed setting a bit rich, so after a couple tanks I leaned the low-speed needle in 1/8 turn increments until I got smooth throttle response with no stumbling. I think my low-speed setting is now at ~1 5/8 or 1 3/4 turns...but everyone is different.

Make sure you're getting a really good prime....I plug the venturi with my hand, remove the spark plug wire, and crank it until the carb is quite wet.

Also, check your idle trim settings on your transmitter...you may simply not have the carb butterfly open enough to start the engine.

Another important tip....the cooling system does not flow freely enough and things get quite hot very quickly....I added a second pickup tube and exit spout for the cylinder head. The exhaust manifold and muffler jacket are using the original water pickup/exit. I also replaced the stock cooling lines with larger diameter silicon lines for better water flow...this is a common fix.

Good luck with it!

Cheers,
Den