hi,
After 30 trouble free flights, my new 160dz spits a lot of fuel through the carb-intake pipe connection. Intake O rings OK.
Any suggestions?
Thanks.

If the o-rings are OK then its not coming from there.

If the intake pipe-carb connection is leaking then the orings are not sealing. Also you could have a leak from the black plastic check valve or the oil could be coming directly from the carb air opening.

There is Zero fuel air mix going up that intake pipe and only a small amount of oil possibly.

The real question is are you getting oil, or raw fuel? Raw fuel is not in the intake pipe, so the only place this could be coming from is the black plastic check valve on the injector line. If its spitting back oil from the bottom of the end of the engine this is likely coming out the carb intake, and spitting up onto the intake Pipe that goes to the head.

If you have too much oil being spit out then trying leaning the pump just a little and see if it stops it. Excess fuel and oil that is not being spent could spit out the carb inlet. This is a normal thing if its way on the rich side. Otherwise its coming from somewhere else.

Troy Newman
Team YS

Thanks Troy,
It spits a lot of raw fuel. Operation of the engine is hardly affected, so I presume it has something to do with the fuel passage in the throttle barrel, finding its way to leak through the 2 O rings. If you agree with that assumption, I can seal it off with RTV and try again.

No raw fuel goes up that tube. All raw fuel in the DZ engines goes tot he injector.

Its nearly impossible for raw fuel to be coming form the intake tube. There is no raw fuel in there its not even close to there.

Perhaps the throttle barrel seal is leaking? If the throttle barrel seal is leaking then it could be getting raw fuel in the intake tube...but that about the only way I can see it happening. If this was happening then likely the engine would not be running properly. I would be acting up.

Troy Newman

The engine is innocent.
The culprit was a pinhole in the new high pressure fuel tubing I installed. It was located near the inlet nipple.
Morel: Always check the obvious first.
Thanks,
Naftali.

See and I go assume you had previously checked that part.


Holes in the fuel tubing doesn't work well with the DZ engines.

Glad you got it solved enjoy!


Troy Newman
Team YS