Bradh2000

OK guys, here it is.....



I am converting this engine for an airboat. Please no flaming for trashing a perfectly good saw...but I had a saw already and got this from a pawnshop for $20 I want to convert it to gas/glow (thanks for the 85+ pages on that guys).

First Q is "Do you think this is a good gas/glow candidate?"

Second Q is "Does anyone have a simple idea of how to drop the carb prophylactic??" I do not have a machine shop []

Third Q is "What is the smallest prop dia x pitch I could go with??" I want max R's and thrust, but low CG as well.

I will ask any gas/glow conversion Q's in the appropriate thread [8D]

buck1856

My Feedback: (49)

I think it would be a great conversion as long as its not to heavy.I have a converted 28cc stihl and its pushing a 17x8APC at 7400.That thing should swing a 20x10-22x8APC no problem.Youd have to talk to scott at, brillelli engines as he does engine conversions with rubber mounts,ect.
Also get in touch with Ralph at RCIGNS.com(hope thats right).
Try Ken at Lambertsrc.com also.I know how you could do it but you kinda implied you dont have many tools.There are some threads on here about the boot problem,put in rubber boot in the search bar for this forum at bottom of page.Theres quite afew pics of mods.
Actually,in the gas/glow thread the best formula and what the best operation is with this setup i believe is in the first 20 pages or less even.1/3- 10% oil glow fuel and 2/3 reg.gas,4-stoke plug.All the rest is optional hubs,mounts ect...Look at av8tors posts,i think most of his fleet is gas/glow by now.

Ralphbf

My Feedback: (27)

Chainsaws do make the best conversions.

The higher compression the more power and the less Nitro. So I'd put a new set of rings in it.

Because you will not need a lot of nitro the 10/10 Super Tigre fuel will do just fine.

Someone was going to try the gas antifreeze/dryer Heet in the yellow bottle for the
Alcohol so that and 8% oil mixed with some good gas and you would be set.
That is if you don't need the 3 1/3% Nitro.

PS. The red bottle is the wrong Alcohol ... go figure.

PSS. It's http://www.rcignitions.com/ He is worth talking to, call him.

Bradh2000

captinjohn

Looking good...let us know when you fire it up! Capt,n

mmattockx

Looks really good. Do you have a weight for it at this stage?

Thanks,
Mark

Bradh2000

Thanks guys. I am goinig to carry it to work to get an accurate weigh in. If my few remaining parts come in today, I am hoping to test it this weekend.

Bradh2000

It came in at 4.55 lbs. as shown without muffler.

Still working on the muffler situation.

Bradh2000

av8tor1977

My Feedback: (6)

Can't wait to hear about the test drives.... But how are you going to start it??

AV8TOR

Bradh2000

Dang ! I knew I forgot something

I have an aluminum starting cone between the dual air rudders. Just enough to to get a starter on it.

captinjohn

Just put a nose cone on the front shaft towards front of airboat....and use electric starter! Capt,n

captinjohn

Brad, have you run the engine in your air-boat yet? Thanks Capt,n

aero nut

that's a beauty of an engine and I think if I'm not wrong it would be the biggest CC engine runned on GAS/GLOW it would represent the culmination of our invention guys. GOOD LUCK BRADH!!!!!

Bradh2000

Guys,

I tried mixing gas from two different sources and could not get it to mix. We could not stand the anticipation of seeing this thing sitting there, so we fired it up. So we squirted a lil glow in the carbie and man when it popped off, it roared like a lion.

My engine mount proved to be to flimsy for this engine, so I am having to redesign it for more strength. I will get some vids once I get it fixed and running fully on the GG mix.

Thanks for the compliments and interest.

Our meet went well and we had one guy break 70MPH with an airboat running a Dubb Jett 90FIRE ! GO HOOTY !

JohnF

Try 2/3 gas and 1/3 30% nitro. I use this for my 40cc, B&S 4-stroke but it has a wet sump for the oil so I don't need oil in the mix.

aero nut

if you fuel is not mixing maybe your fuel is contaminated with water and makes the oil to separate from the fuel and remember is 1 part glow fuel with 2 parts 91octane gasoline

Bradh2000

I used fresh high octane gas right out of the pump.

I am mixing one third 10% nitro 18% oil glow fuel (new bottle) with two thirds high test gas.

I know this oil content is too high, but I have some methanol on hand (Heet Yellow bottle).

I was hoping the mix of 5%nitro w/ 9% oil and Hi-test gas would be OK since this engine has high compression.

I have some old 15%, but feared it may have absorbed some moisture over time.

Thoughts????

aero nut

I would mix 1part glow fuel and 1 part heat(metanol) this would make your glow fuel 7.5% nitro and 9% oil then I would go ans take 1 part of this mixture and mix it with 2 parts 91 octane gasoline; at the end you will have aproximately 2.5% nitro, 3.333% oil, 27% methanol and 66.6 % gasoline which wil work fine with the engine. but remember to mix the heat and the glow fuel first, one question though is Heat pure methanol or does it have other ingredients in it, because these other ingredients may cause the fuel to split just my guess, but go ahead and make a smal batch and see wath results do you get.

Bradh2000

I researched HEET and found info indicating it was 99% pure methanol, but it cannot be sold as pure because of methanols ability to absorb water from the air?? Go firgure. I am in racing country (Karts, NASCAR etc) so metathanol should be easy to find if the HEET does not work.

Question that may have been asked/answered in the 90+ page thread [:@] Does the mix go cloudy before going clear? The first batch I mixed appeared somewhat mixed/clear. The mixture appeared to swirl like a real good marguarita but went cloudy and then seperated (water??)

Thx for the help guys. I am about to convert a 3.4CI Sears (poulan?) saw. It has been trimmed and just needs a prop hub, prop, spark adaptor and a custom mount.

I am thinking of sticking it on one of these

aero nut

it should mix clear otherwise it seems that there is water in your gasoline!!! try different gas station or brand

Ralphbf

My Feedback: (27)

There was one other guy that had separation issues.
I beleve he was from the South Eastern part of the country.

It was the brand of gas. Here in California I have used different brands and never has this problem.
And I don't remember which fuel was in question.

You mat try racing fuel, I use to purchase it from a local gas station, the owner raced go-carts.

Keep trying, success is just around the corner.

Bradh2000

Well guys, I have not totally forgotten this project and finally got the kit.
I have the new motor mount/stand fabricated and ready for welding.
I will post pics with the new mount shortly.

Bradh2000

Update

av8tor1977

My Feedback: (6)

Well, I gotta tell ya, when I saw your first posts and the mounting, I thought "oh my god, poor guy." "He has put a lot of work into that mount, but I don't think it is going to work; looks way too flimsy." This mounting looks a lot better. Just make sure it is really anchored well at the bottom with doublers and such where it goes into the wood.

Keep us posted. I've seen videos of this boat in action and it's cool. I've thought of doing one myself. What did the kit for the boat itself cost?

AV8TOR