( if your a pesky rush rush type . go to bottom & up 13 to SUMMARY . We assume others are entralled by deatailed explanations .
)
Guess ive flown the G - 51 as much as any other engine , this century , at least .
Had one in a 2 kilo ' Hurricane ' thing running a 13 x 5 or so APC 'dagger 'prop .
Usually run 5 pitch but 10 or 11 or 12 , 3 or 4 blade , 12 x 5 2 blade T F wood .
HOWEVER , as Brett says ! OIL .
First hour or twos running , the 30 / 25 oil indeed . But the most run one , ive
used a lot of cheap ?? comercial fuel . Hot Stuff etc etc ( brand ) which might be 18 % oil .
So cunning sods actually go by the WEIGHT im told , to write a larger number on the lable .
20 % Weight isnt 20 % volume , we're told .
Whatever .
This Engine has NO WEAR on the RING . Sits at 5 thou. clearance , on a recent strip & inspect .
Mustve used say 10 Imp. Gallons so far , not a lot but not insignificant .
TWO THEORIES ive read ,
1/. Backplate radial gap - Fuel Oil accumulation - Ungloops under high strees ( like you get in wind )
and ' dumps ' Rich cut & plug foul results .
Maybe so . Particularly with excess oil .
2/. Excess oil . theory . 18 % recomended . ( from my observations this is no problem at all . WEAR
is not going to be an issue . Grit Ingestion is to be avoided - screen on intake if 'desert / dusty 'use ! )
same bleedy issues , up in the backplate & dumps , so we're told .
3/. Mangey pattern Enya Plugs ! these work for six runs . If your lucky . Then do as yours does .
SO MATCH YOUR PROBLEM PRECISELY . While we're on PLUGS , if theyre white & chalky , theyre past it, and'll DO THAT .
4/. BEARINGS . Ive had to replace 10 year old bearings . As they DO THAT . If the bearings feel at all notchy in the least
this could well be the problem . Ive had it . story is minute metal particals 'short out 'the plug . Like they do . Not Unusual .
My engines are always afterun oiled . but if youve an 'of season 'where it is UNFLOWN , unless its been thoroughly rinsed , the NITRO RESIDE
is CORROSIVE , hence disintegrateing bearing surfaces - forign matter - metalic - Plug trashed . Litte brown or black speks on the element .
So there we are .
Start up , aFTER AFTER RUN OILED , ive found if I pull the plug ( Its OILED ) flush it , and give the engine a generous flooding prime , say 20 cc .
turn through 10 times then belt through / spin over ten times . WELL , six at least of each , anyway . She fires up straight of , into a clean run .
Whereas if you dont the after run oiled plug aint gunna do the trick till its cleared after faffing around some time .
While where at it , the 'element Pushed Back 'into the plug - is generally said to be from to much Comp. ( ratio ) .
however , Uncleared of storage oil , the hydraulicing can do the same thing . Push the element back into the glow plug .
So there you are . SUMMARY . 18 % oil is plenty ( at least untill 30. C. Atmo temp . maybe add a iota in a heat wave )
=======
Your best with at least 3 % Castor or Syn. as precaution . Usually Half Each Syn. & Castor is a safe bet .
PLUGS . Check Them . White & Chalky element , its trash for stunt .
Watch yer Bearings - Theres no uva real ''issues 'wiffem .
====================================
My only rotten run thing was into insides in owling gales . Stock Intake about level with the 3 inch spinner edge .
A sort of rich cut ? baulk , hestitation . Into up leg of inside squares . When it were windy as eck , near two hand
stuff . Like 18 Kt costal , hard & billowing . Old on tight & dig in your heels stuff . Mightve been 'Cumulative'
Bob Gieske & cohorts ( one stunt fuel supplier ) ran some ( a few % ) of 'keep it going 'range extender STUFF ,
not ipa or petrol . Slips my mind at the moment . But was definately 'anti flame Out '. Bob Hunt was in league with the supplyer so should recall the stuff . Maybe Lighter fluid ?
Versatile engines these G-51's . But the first thing I did on my Bunged Boost one was UNBUNG it , merely a personal preferance , an 'as its made 'is goodenough .'
Only Other Issue I can see with them , is a big tank level with the stock spraybar in the venturie , vertical mount . Close in . Could Obstruct 'through flow 'of cooling air .
The Big Jim / Urtnowski . And by Bob Gialdini , Cowl Top ventilation , to stop percolation / fuel vapouriseation . Parked . For good restarts & running case pump efficiency
in worth a thought .