JAE .91 maiden.

Vince Fantauzzi · May 16, 2020

Hey, guys, need a need a lil help from someone who's a bit more knowledgeable on OPS engines than I (which is probably everyone on this db lol).

I finally got a chance to take my new jae 91 build to the lake. The engine ran well (set a lil rich) on the stand. At the lake with a gentle toss the rigger got on plane withing a few yards and ran well for a couple of short laps and then it sputtered a stalled. Checked fuel connections, throttle linkage, and tank air line...all ok. Tried again.... same results. Any ideas.

brad nichols · May 16, 2020

Could be anything from plug to prop. I had a plugged pressure line that was a problem to pipe to short, lines too small, pickup to close to wall in tank, bad bearing.......etc. Not enough info

Brad

Terry Keeley · May 16, 2020

Take the plug out carefully so as not to touch the base and see if there's a drop of water on it.

Did it quit at the same level of fuel each time?

Ray Sametz · May 16, 2020

If on the back straight at same spot check radio, fail safe could be kicking in. Just a thought...........

Vince Fantauzzi · May 16, 2020

Terry Keeley said:
Take the plug out carefully so as not to touch the base and see if there's a drop of water on it.

Did it quit at the same level of fuel each time?

Yes, pretty much...water in the carb did occurr to me sometime later... but I took out the plug with out checking, to drain the engine, as the engine compartment got flooded when my rescue craft pushed it to shore. The carb air intake is somewhat exposed.

Vince Fantauzzi · May 16, 2020

brad nichols said:
Could be anything from plug to prop. I had a plugged pressure line that was a problem to pipe to short, lines too small, pickup to close to wall in tank, bad bearing.......etc. Not enough info

Brad

Yeah, I figured it could be one of a bunch of different things... gotta start the elimination process's, I guess. Couple of pics of set up.

brad nichols · May 16, 2020

Your carb is way TO close to the bulkhead or is it open? Rule of thumb is an 1'' of clearance around the front of the carb.

Brad

Larrykent · May 16, 2020

I would also make sure the fuel lines are of the same material.
It looks like you have gas and nitro fuel-air lines..gas lines get hard after time and leak

This could help.
Keep us posted
Lk

Larrykent · May 16, 2020

Change the rubber on the tank
I bet fuel gets as low or lower than it , then it sucks air.

Vince Fantauzzi · May 17, 2020

brad nichols said:
Your carb is way TO close to the bulkhead or is it open? Rule of thumb is an 1'' of clearance around the front of the carb.

Brad

The bulkhead is open.

Chris Wood · May 17, 2020

quick and dirty.. take the filters off and try again. that will eliminate one thing quickly

Chris Wood · May 17, 2020

also myself.. never had any luck with plastic tanks.. i know people use them but have seen to many issues with them in the past. if you can get someone like walt barney to make you s/s tank that would be a good option also.. see alot of pick up issues with plastics over the yr's

David Murany · May 17, 2020

Where does the 3rd line from the tank go? Most of the time you only have a pressure and an outlet to the carb.

Have had this type of problem before and it was a cracked line inside the tank. It would always die with the same amount of fuel in it.

FloridaScaleBoater · May 17, 2020

David Murany said:
Where does the 3rd line from the tank go? Most of the time you only have a pressure and an outlet to the carb.

Have had this type of problem before and it was a cracked line inside the tank. It would always die with the same amount of fuel in it.

DITTO the question, what is the 3rd line on the tank for?
When ever I seem to have a fuel draw problem, the best test I have found to detect them is this:
1) Fill tank/tanks completely with fuel.
2) place the boat on a work bench, table. and elevated location.
3) hook your pressure lines up as they would be while running.
4) make an extension for you fuel suction line (the one that would normally go to carb. nipple. Long enough to go the the floor, back into a fuel jug.
5) start the fuel flowing by siphoning, let it drain naturally back into the fuel jug.
If it stops before the tanks are completely empty or you see air bubbles in the flow. You have a fuel draw problem.
****On multi tank systems, if you sump/hopper tank drains before one of your main tanks. You have a fuel draw problem.

John Beardslee · May 17, 2020

David Murany said:
Where does the 3rd line from the tank go? Most of the time you only have a pressure and an outlet to the carb.

Have had this type of problem before and it was a cracked line inside the tank. It would always die with the same amount of fuel in it.

The third line maybe for a “Uniflow” tank system, they were popular in that era. If this is a boater new to the hobby setting up an older nitro boat, I suspect the needle is still set too lean.
Thanks John

bermudadude · May 17, 2020

im only gonna say this once GET RID OF THOSE FILTERS. [at least the pressure one]
filter fuel into the tank and run the boat.
also i dont see why anybody would filter the pressure line. looks like the line goes thru a bulkhead then into the pipe(??)
fuel and pressure lines should be soo short they are actually an inconvenience .
"IF" the carb is stock the spraybar is too small for any real amount of nitro% the hoses cant be too small and too long

Vince Fantauzzi · May 17, 2020

The filters are brand new and they are clean. The third line is used to refill the tank. Did this so I wouldn't have to disconnect and reconnect lines. This line is plugged when boat is running.

Brad Christy · May 18, 2020

Vince,

My suggestion would be to ditch the plastic tank and dedicated fill line. They are nothing more than opportunities for failures. I use stainless tanks exclusively. I remove them from the boat to fill them. This allows for assuring they are completely filled by holding them at an angle so that the pressure line is a the highest point, as well as prevents the spilling of excess fuel in the boat.

Just a thought.

Thanks. Brad.
Titan Racing Components
BlackJack Hydros
Model Machine and Precision LLC

Will Gallagher · May 18, 2020

All good suggestions, but it sounds like the engine is building heat and going lean due to lack of fuel.

1) Use Large fuel line (no filters)
2) Set carb to 1/3 open at idle
3) Adjust needle so the engine sounds rich to the point you need to tap the throttle to clear it..

I bet you will have better success with this set up...

Just my 2 cents...

Vince Fantauzzi · May 18, 2020

Thanks for all the input, guys...once the weather clears up here I'll head to the lake and implement some of these suggestions and see if I can resolve the problem. Will post outcome.

Vince

JAE .91 maiden.

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