Stock OS.

[Bill Britton]

Whats a good starting point when flowing a stock OS? I don't remember.

 

[Robert Pickard]

Bill on the Boris Flow it starts at 107 to 135

 

[Bill Britton]

Great! I have a Boris meter. Thanks!

 

[dave roach]

Bill

Start at 120

Dave

 

[steve palgreene]

All boris flow meter do not read the same I set mine at 160 to 170 friend of mine has same flow meter do not read the same off by 20 he set his at 145 . I try to set it at 110 to 140 to rich boat does not go have to lean it up to make mine go.

 

[Robert Pickard]

On any Boris flow the low number is the rich number

 

[steve palgreene]

Yes I know lower the number but the boat does not go fast when that rich they drive away of me in the race.

 

[BradSpencer]

So many factors at play here.

Water cooled or air cooled head? If water cooled I restrict water to 60 on my BM 3.

V1 or V2 muffler? With a V2 muffler the mixture will need to be 10 points richer over the V1.

On a stock power head with V2 muffler, I keep ending up at 140 on the BM. I always set the low speed needle so it flows 150 on the BM at idle.

The need to run extra lean on these engines to get RPM is usually because of to much prop, or the setup is creating to much drag/load.

Worth checking bearings, and for piston/head detonation and pitting as well.

My 2 cents

 

[Wally Marsh]

And remember the stock sleeve is nickle plated not chrome, will not last with lean runs. I run my V1 hot and feed it the fuel, water restricted to 0.020 outlet measures 120 on my Boris Gen2 meter, fuel flows around 95. I used a plastic collar with 8-32 thumbscrew on the water line to find my settings the first few years. These motors need lower pitch props and need to spin for power, but a great motor for .21 tunnels Sport even mod class if set up is there.

My $.02 before taxes