Fast Fred's OMC Mod 50 secrets Thread #2

[Fast Fred]

Tim Kurcz, what is that right before the cool can, right after the pump?
and what is that at the top of the fuel rail? ( just after the carbs)

thanks
FF

[850cc racer]

thats the regulator. it goes- filter -pump -reulator.

then after the carbies is an orifice

[sheuninck]

last i knew, ya can't run a cool can in any class of SLT, so was not thinkin of that in my set up.

i choke her up with a squeeze bottle, like a Funny car, got to take the hood off,
no choke circuit on there, you should see the look on them couch boat peoples faces at the ramp

i did not see the rule against cool cans. i will take a look

[Fast Fred]

the rule book is short for Bandit and Outlaw, if it don't say you can, you can't.
it was talked about for "X" and voted down.

[850cc racer]

okay so its late here and i have a question:

Mr Kurcz has advised us he runs 16:1 oil.
Mr Fast has advised mod 50 book says 50:1

my question is: the life span i think i read fred saying 50 hours of WOT?

with more oil less friction does this make the engine live longer?

so 50hrs of WOT @ 50/1...

xx hrs at 16/1...

might be a dumb question but i want to ask.


850

[Fast Fred]

for me, just my .02, more oil make more of a mess. kind of oil makes more of a dif'
semi synthetic at 25 to1 makes a mess all over her self.

[Powerabout]

more oil = less friction?
Less friction = less metal to metal contact
more oil = rings seal better
better ring seal = more power
( more power = finish race earlier so less engine hours)
more power = more heat/pressure?
more heat/pressure = ?

I am suprised the MOD 50 manual says 50:1?
every OMC race engine manual I have seen says 25:1
I think the evidence on this site and many other 2 stoke sites says there will be more power all the way rich till 16:1

[850cc racer]

Fred making a mess.. Mine made a mess when she had a weak spark on one. Changed that and she was all clean.

Has had a few idles on trailer no mess... Then a 'putt' on the river with too much fuel and no mess.

Powerabout: more heat i disagree with on avgas its keeping temp's down..
Did u get your housing?

[Powerabout]

Ya cant make more power without more combustion heat as thats what expands the gas more.
(all other things being equal)

I think the guys were talking that the latent heat of evaporation of avgas is better than petrol ( I dont know) so when it changes state from liquid to a gas it pulls in lots of energy, i.e. heat so therefore cools the air down for better volumetric efficiency so more fuel, more air, bigger bang, more heat, more expansion.

If you are running an engine on the dyno and the dew point is very low you can see ice forming in on the carbs especailly using methanol.
Remember carby heat on airplanes, lower air pressure lowers the boiling point of the fuel and the dew point.

Re Housing
Wifey banged herself up sailing on the weekend so is down for the count.
She will go tomorrow if she can, thanks for checking.
I am out of town at the moment.

Cheers

Powerabout

[Mark75H]

Latent heat of evaporation of AV gas is essentially the same as street gas