Carb / Pipe Question sport 40

[Rick Reisinger]

I have a MAC .45 with one of Andy Brown 40 Quiet pipes on it ,

The engine acts and run's real rich at start up at idle looking at the carb it is drowning after I get it in the water seem's to be fine for 2 laps then leans out > Suspect to small stinger on primary pipe building to much back pressure on hole in spray bar to large .... Question spray bar ID ? Stinger ID ? should be ??

 

[dave roach]

Rick

Are you running the 5/32 fuel lines out of the tank and bigger fuel line..If you are running the 1/8 lines it will do the same thing.

 

[Rick Reisinger]

Dave

I am running the larger line

 

[SayMikey]

How old are those bearings? Make sure the case to crank seal is not destroyed

 

[Rick Reisinger]

New Bearings Mike

 

[Brian Sorgente]

Here are some ideas.

Check fuel tank for leaks by looking for any bubbles in the line while pumping out the tank. You can do a siphon test to check too. Fill the tank and run a line to a cup below the level of the tank then blow into the vent for a second to get it going then and let it drain. If you see bubles or it stops draining, your tank has a cracked line or broken seam on the internal hopper.

Check all o-rings, look for debri in the needle, make sure your piston has a good seal, fuel line could have pin hole, your fuel filter o-ring could be bad or the filter could be plugged. Try a new glow plug. Could be over heating, is it getting water? Whats your plug look like?

Brian

 

[Rick Reisinger]

Here are some ideas.

Check fuel tank for leaks by looking for any bubbles in the line while pumping out the tank. You can do a siphon test to check too. Fill the tank and run a line to a cup below the level of the tank then blow into the vent for a second to get it going then and let it drain. If you see bubles or it stops draining, your tank has a cracked line or broken seam on the internal hopper.

Check all o-rings, look for debri in the needle, make sure your piston has a good seal, fuel line could have pin hole, your fuel filter o-ring could be bad or the filter could be plugged. Try a new glow plug. Could be over heating, is it getting water? Whats your plug look like?

Brian

Neat idea on testing the tank Brian , I will try that one my friend 2ND needle I have tried same thing > I checked the pipe .470 stinger size > carb spray bar I/D .080 .... Let me know what you think > What is the common I/D for the id of the spray bar ???

 

[Brian Sorgente]

Yeah Walt barney told me that at the nats in 2012 and it works very well. I had a bad tank a couple years ago and i chased it all season...Drove me nuts...

Anyway, what pipe are you running? Im no expert but 0.470 stinger ID seems pretty large to me. The few 45 pipes i've seen vary around 0.340 to 0.435". As for the spray bar i beleive the sock mac45 spray bar was 0.093".

Brian

 

[Rick Reisinger]

Yeah Walt barney told me that at the nats in 2012 and it works very well. I had a bad tank a couple years ago and i chased it all season...Drove me nuts...

Anyway, what pipe are you running? Im no expert but 0.470 stinger ID seems pretty large to me. The few 45 pipes i've seen vary around 0.340 to 0.435". As for the spray bar i beleive the sock mac45 spray bar was 0.093".

Brian

The pipe is a Andy Brown parabolic {Quiet Pipe } , I thought it would be a good marriage > Gota figure out why these two are not getting along, LOL .

 

[Brian Sorgente]

Are you sure its the 45 pipe? I have a few parabolic pipes and I know the stinger diameters were updated from the early generations to the later ones. Early gens started with 0.344 ID I believe and later ones got as big as 0.435. I'd have to check but I'm not sure you could even bore one to .470. If you can, I imagine the stinger wall would be very thin. I will check tonight.

Also I know the spray bar diameter was 0.093 from CMDI. I confirmed this with Andy a couple years ago when I got my mac 45 to make sure nobody messed with it.

Brian

 

[FloridaScaleBoater]

Bore the internal stinger to the same size as the outer stinger, I believe it will end up being 1/2".

 

[SayMikey]

Are you getting enough water. Is your strut sealed.Run it without the cowl and see what happens

 

[Brian Sorgente]

I checked the stinger on my 45 parabolic pipe this morning (latest generation which is the largest) and the OD was 0.506". So if your stinger diameter is 0.470, that only leaves you with a 0.018" wall on the outside. I imagine the internal stinger is probably gone too? Or could you possibly have a 67 pipe and not a 45?

 

[Rick Reisinger]

Every thing corrected { I hope } testing today ... > something Else I ran across is this on the pipe ~ 10 3/4 is very conservative. But we found that milling for clock time was easier and helped with Torque.

10 5/8 made very little change.
10 1/2 we lost torque and could not mill for the clock.

All of this with a MAC 45 on 50% Nitro. AB Parabolic which is the same as the A/A pipe. X647, and X450. It might have been a X648. Not sure on Altitude.