captinjohn

I just ran my Homelite 25cc on 10% Glow fuel. She starts real easy...most times 1st flip. The RPM was over 8600 on 1st run. The only thing it wants to start and run backwards most the time. I am using a Supertiger 90 carb which plugs right into the manifold spacer after sanding to correct size using a dremel sanding drum in a drill press. The carb seems to adjust real good. The idle was fairly slow but did not sound right untill I gave it some back pressure at the open exhaust port with a piece of wood. It then would idle super smooth and at a very , very low RPM. I will post a photo of it hear soon. This engine is so far a freebe...using parts on hand. Like supertiger carb! Next test will be with a Walbro type pumper carb. Then a gas/glow fuel mix. GGL for short. Thanks Capt,n

davewallace

My Feedback: (29)

Captain,
What size and brand prop did you use to get these figures? Did you do any other mods to the engine?

Dave

captinjohn

Engine...older (low time)25cc Homelite. I have done no mods to the ports or timing. Did eliminate gaskets and used Yamabond. I have to get or make a exhaust for it. I am sure a little bigger carb could be used. Have not tried muffler pressure yet or the perry inline pump that works off crankcase pressure. Lots of options to try yet!!!! The prop is a 16x6 APC. This engine does not seem to be a nasty kickback type. May get a boman piston ring. Capt,n

av8tor1977

My Feedback: (6)

Interesting experiment to use the Super Tigre carb Cap'n John, but to tell you the truth I've never had a problem running "Gas/Glow" with the Walbro carbs. I also like the fact that they have a pump built in for steady fuel supply. I usually mount my gas tank farther rearward than normal, about on the center of gravity. That way there is no trim change as the fuel supply gets used up.

If you decide to go with a Bowman ring, I have had great luck with the 25cc Homelites by ordering a ring for use with a pinned piston from him. I then use a piece of .063" gas welding rod to make a pin for the piston so the ring can't turn. Then you can grind out that bridge in the exhaust port for better flow.

I also have had problems with these engines converted to glow quite often wanting to start backwards. Usually flipping the prop to start in a backwards direction will make it backfire and run in the proper direction, or just a quick touch from an electric starter has them going the right way. I had one the other day pop and start back up backwards as I was shutting it down with the transmitter trim. It then backed up into a wall, so be sure you have the airplane secured both fore and aft when you start or run them. They sure start easy and idle slow running on glow don't they?

Have fun,
AV8TOR

captinjohn

av8tor1977: The Supertiger 90 carb was just a thing I wanted to try. Not because I like em better than a walbro. Regular glow carbs have a advantage in some ways. They can pass more fuel without messing with the innards of a more complex carb. No diaphragms to go bad from different types of fuel I am going to try. Walbro with pump to deliver fuel looks like the easy way out. The gas/glow test is next (but before I do that) have you ever just mixed 1 part of glow fuel to 2 parts of strait alcohol? If so what was the RPM? It looks like the price of alky may be the same or less than gas!! Capt,n

davewallace

My Feedback: (29)

Captain,
Here is an interesting test that you could do. We know that glow engines flood easily when inverted. Flip your glow Homey over and see how easy it is to start. Just a thought since most gas installations are inverted.

Dave

captinjohn

Dave: Good Idea. I will flip it over and try just that. It likes to be wet for starting. Maybe inverting it will help!!!! I have not tried a 4 cycle plug yet also. Regards Capt,n

av8tor1977

My Feedback: (6)

I have a Kioritz 23.6cc in a Katana, and another one in a 1/4 scale Fokker Triplane. Both running "Gas/Glow" and both inverted. No problems...

AV8TOR

captinjohn

I would venture to guess because of the very low oil content compared to regular glow fuel...the oil does not collect around the glow plug as much in the inverted position. This low oil content is very good. Not much to clean up on plane and less$$ for lube. Less carbon build up too. A win-win deal. Regards Capt,n

KidEpoxy

if you attribute better inverted running to less oil, should I be concerned about a high oil inverted engine?

I'm trying to get all my ducks in a row with a cox 049 on GGL, but it would need massive 20%+ oil ... should I steer clear of Inverted mounts?

davewallace

My Feedback: (29)

yes

captinjohn

I ran the Homelite 25cc Glow in the inverted position. It starts with one flip after running. I see no problem whatsoever with it inverted. May have even run better. I do have to get a muffler on her. It does not hold the heat of the glow and will stop on a idle. If I cover/block the exhaust port she runs smoother and does not quit then. The same in all 3 positions...even sideways. Electric starter always gets it going in right direction. Although in the invert position... it seem to start and run the right direction by hand flipping. Go figure??? More tests later. Capt,n

davewallace

My Feedback: (29)

Captain,
Now will it run as well with a Wallbro 11mm pumper carb. That will fix your suction issues. How is fuel consumption? What brand glow plug adapter did you use?

Dave

tkg

My Feedback: (1)

Good bacic approach , but bigger is always better. See if you can score a ST3000 carb or a Big bore Perry. The later 3000 carbs had an insert to help fuel draw on the 2500 seris, so you could change your carb size even more to experment with.
Oil should be in the 5% range

captinjohn

Dave: Fuel comsumption is not bad. Throttle response is super fast. No adapter....redone head. TKG: I have no bigger glow carbs on hand. I used Omega Castor/Synthetic 10% Nitro Glow fuel with way to much oil in it. I guess I may just cut the Glow fuel with gas....and try that tomorrow. Capt,n...Over and out! P.S. I will also try a Walbro....I got 14 of them...but got to sort out a good one.

cochinito77

what ever happened here?

captinjohn

I kinda got side-tracked. Too many irons in the fire. I got to get a good eshaust made before I do any more testing. Got to have that muffler. I got close neibors here and do not want to upset them also. Best Regards, Capt,n[]

cochinito77

hey capt how do YOU make your exhausts? buy em make em you must be a welder if you do right?
thanks keep us updated-Raf

captinjohn

I do not have a welder. I cut out the parts and pay a poontoon boat builder to weld it together. Capt,n

cochinito77

doest it run expensive cause its just thin walled aluminum right? that sounds el cheapo right up my alley!

captinjohn

Well I ran the Homelite 25cc (glow version) some more. I built a new test stand. I was able to tune it more. Still have the Supertiger .90 Carb on it. I like the Idea of being able to set the needles for a wide variety of fuel. I am now ready to do the Gas/glow fuel test. The only thing I don not like is a bad vibration at about 1/4-1/3 throttle. Top RPM and Idle seem pretty smooth. Maybe I will check crank for balance somehow. Any Ideas? thanks Capt,n[:-]

davewallace

My Feedback: (29)

Captain,
Not much can be done to balance the crank. The counter weight may be a little lite for running without a flywheel. You can increase the effective weight by grinding the crank pin boss round, grinding off the excess lenght of the crank pin and stuffing the case to keep the rod on the pin. Adding a stuffing plate to the backplate or cutting about 1/8" off the back of the case will do this. You can also lighten the piston. Has anyone had vibration on their electronic ignition Homelites? Prop balance and tracking or heavier prop may help.

Dave

captinjohn

Is there a place i can remove weight on piston and improve port timimg. Also do you grind off crank on throw of crank...and not the counterweights? Thanks Capt,n

captinjohn

It was a hot day but I built a more serious test stand. Should work for up to 150cc engines. Cost $5.60 and the rest was all scrapts. Capt,n

captinjohn

It was a hot day but I built a more serious test stand. Should work for up to 150cc engines. Cost $5.60 and the rest was all scrapts. Capt,n