Uni-Flow Mod Pissing Me Off! Any suggestions?

[MustangMan]

Hey all...

I installed the uni-flow mod on my Savage the other night after installing a new backplate and the HPI engine stop. I know I have the one-way check valve installed correctly.

I put fuel in the tank and tried to prime it and it hydrolocked on me. I pulled the plug and removed the fuel and tried again, just to hydrolock it again.

Before I knew it I've got fuel soaking into the air filter from the carb and raw fuel coming out the pipe. I drained about a 20% full tank in a matter of minutes trying to start it.

I got frustrated, pulled the check valve out and the the rest of the uni-flow parts, drained the fuel, cleaned everything up, and tried to start the Savy my normal way and it lit right off. I ripped around the yard for another quarter of a tank with no problems.

So, the Savy is on the shelf with the stock fuel lines on it right now. I just can't figure out how I screwed up so bad.

I noticed I couldn't leave fuel in the tank either, as it would expand into the carb from the garage heat over time.

Maybe the uni-flow just isn't for me? Any suggestions?

Thanks...

 

[Candyman]

May be just that you're overpriming it. When I had the uniflow on my Sav, I would only have to turn the engine over TDC once or twice before I saw fuel running up to the carb. When you plug the stinger, the amount of pressure you're sending to the tank is pretty high so you don't have to tug at the starter cord to get it to prime.

 

[rossb]

I have been running the Uniflow mod for well over a year and I have no problems with it. See HERE for pictures of my setup. A few comments:

* You do not need the one-way valve. Run a long pressure line instead.

* Do not leave an un-running uniflow truck sitting for extended periods of time with fuel in the tank. The fuel will flow into the carb or the pipe. Pressure in the tank has nowhere to escape. You should never leave fuel in an un-running truck for extended periods of time anyway, even without the uniflow.

* To prime the motor pull the pressure line off the pipe and blow into it. Stop blowing after fuel reaches the carb.

* Put on your glow ignitor, leave it on the plug for about 10 seconds, and then start pulling. The motor should start on the 3rd or 4th pull if you have a good tune and a good glow plug.

 

[MustangMan]

Well...

I figured I would use the one-way valve instead of having 10-inches of fuel line running all over the truck.

I have the rotostart on my S-25 (RTR) so maybe holding the stinger closed like I normally do puts too much fuel into the crankcase?

I'm pretty busy most every night this week, but maybe this weekend I'll put the uni-flow parts back on the truck and try it again...

Thanks...

 

[arawak420]

i had problems with the uni-flow mod as well. i dithced the idea casue my truck would not move very fast. i think it was a worse idea than stock.

i ran a 22" inch fuel line hose from the exhaust to the gas tank. i ran the fuel tube from the exhaust around the front shock tower to the gas tank. pressure is good and i doesn't lean or die when i open the gas lid. i ran a longer tube from the tank to the carb as well.

like you the uni did not work for the I. wasted $5 on a one-way valve.

 

[Tarant]

Here try this I did it and it works better then a checkvalve. https://www.rcnitrotalk.com/forum/showthread.php?t=20546&highlight=uniflow

 

[rossb]

Thats my post.

 

[olds97_lss]

The checkvalve just causes problems with flooding as you found out. I tried one on my maxx a couple times and it made it run really rich regardless of tune and flooded often.

You could always try a different tank...

Personally, I only ran the stock tank for about 4 tanks worth. Then I got new era upper arms and UE SuperMaxx shocks, but only run 4 of them. This opened up room by the tank so I could install a buggy tank easily. I've been running this way for about 11 gallons (since last year).

 

[Tarant]

Thats my post.

I know it has Great pics, and info.

Thanks.