because it's a normal airplane setup, the props are cheaper (not to mention that's the only props I have) and was the way the boat was set up.

Tractor configuration airboats also cool the engine much better.

AV8TOR

Yeah I was reading about the props last night.
Makes sense if the other props are cheaper and making use of what you already had.

I went camping this weekend and took the boat with me, only problem was with the altitude... normally I'm at 200' ASL and the lake I was at was at around 2500' ASL so this non adjustable carb didn't let the engine run very well on the top end (idled great), it only ran to about 15-20mph, but it didn't flip this time I think the COG adjustment fixed that problem.

Sounds like you got to run it a bit I am sure it was fun.
How does it handle?

doesn't turn very well against a healthy breeze, otherwise not too bad, just takes some getting used to

The increase in altitude should have made the engine run rich. Next time try taking the air cleaner off when at altitude and see if that doesn't lean it out enough to make a difference.

AV8TOR

They look like fun to drive and play with, I look forward to possibly building one of my own.

yeah, it was running too rich, only ran it for about 15 minutes but didn't think taking the filter off...

Hi, I could of (still could) pick up several B&S 4 stroke weed eaters from the local small engine shop. No way of knowing what condition the engines were in, but they were free for hauling away. In your opinion are the B&S worth fooling with compared to other 4 strokes or 2 stroke conversions? They would be interesting enough to fool with.


I did come home with three Ryobi four strokes; one with the round oil sump/crankcase, one with the magnesium oil sump and one with the plastic oil sump. Have you had any experience with these?

Thank you very much.

Sincerely,

Richard

well, it spins that 15x8 prop at 6400rpm which is supposedly around 6 pounds of thrust so about the thrust of a .50-.60, looks pretty clean though, only downside is the mag being mounted to the bolt on fan schroud, would look cleaner if it was part of the jug.

I only have one ryobi 4 stroke and it's in a weedeater and it'll stay that way, has the nice two needle carb on it.

downside of these 4 strokes with splash oiling is they need to stay upright or close to, so they need to be in a cub or trainer or something, which is why the one I used got put in the air boat . The crankcase makes mounting rough which is why I just mounted it by the schroud...

finally got some vids of the boat in action:




at the end of the second video you can see it flop... it was fine afterwards, only problem is the top plywood sheet is unglued from the foam again... I'll have to figure out a better solution for that issue... I have some ideas.

this thing doesn't use any fuel... I think I've put about an hour on it and have gone through about a tank...

Nice seems to handle really well!
Nice little pond just big enough to do some figure 8's........
I keep wanting to see it hit the bank and try to climb up it, grass probably to tall and you still have the fin on the bottom?

yeah, it doesn't move at all on grass with that fin thing, it's only about 1" tall but that engine doesn't have enough power to overpower the drag... apparently a bit too top heavy still though...

Heres a a few pics of a similar Ryobi I did last year. Set up to run gas/glow. Turns an 18-6 well over 7K. I would suggest dumping the stock carb. Runs very well on a 2stoke 2 needle carb. The carb on this one is a WT 220 off a Homey weedeater I believe.

I have three Ryobi 4 strokes to be converted. One with round sump, one with angled metal (magnesium?) sump and another with angled black plastic sump. Do you know the difference between them and which is the best for conversion with the most power. I Am very interested in gas/glow, but heard the Ryobi spark plug is very long and deep set. How did you set up the glow plug, and do you run power to the glow plug all the time or just for starting? What glow plug are you using? What fuel mix are you using? Have you tried Coleman "gas" with glow fuel?

Thank you very much.

Sincerely,

Richard

I dont have a lot of experience with the 4 strokes. I do know that the earlier ones like this one have a removeable ignition mount while the later ones require cutting. Also I believe the latest ones have more displacement, maybe around 30+cc? The glow plug adapter was made from the stock spark plug, with the head turned off and cut down as close to flush as possible to get the glow plug to the lowest position. I am running the usual OS F plug. The gas/glow mix is the standard 66/33% mix. I have tried 15% Cool Power, but the best results were with 30% Cool Power heli fuel, woke it up a little bit. The heli fuel is oil rich @ 24%, but didnt seem to bother it. I suppoose the best fuel would be home brew, with a little oil and an amount of nitro to be determined by testing. I believe I would start with 6 oz oil and maybe 20% nitro. I have run my 30cc Homey on home brew and it wasnt very happy with 0% nitro. I mixed Cool Power into straight methonal until I got approximately 10% nitro, then mixed it to the gas. This made the Homey run pretty well, the oil content of the glow fuel was reduced somewhat which I felt improved the running. For what ever reason the 4 stroke seems to like higher nitro. The local kart shop closed so there is no local source for nitro. I havent gotten around to ordering any, even though I still have several gallons of methanol around. As to Coleman I like it for my gassers. I fly a gasser heli on it and it runs great, plus I can bring it into the house to work on it without divorce papers from the old lady. I have flown it in some of my planks where it works pretty well. Some careful testing on the stand shows it makes about the same power as gasoline, but gasoline has a slightly better idle and transition. Not that the Coleman was bad. As to using it in G/G, I dont know. Coleman is simply naptha, also known as "white gas" I believe its main draw back is it octane is around 55, so listen for detonation. I have not heard any in my use of it. The + side it is very stable, keeps for a long time. leaves no residue, and doesnt affect carb and fuel tank components.

Forgot the question about lighting the glow plug. I have tried it both ways. It runs well only lighting the plug to start it. Idle is good as well as transiton. However it will idle much lower if the plug is kept lit. Not that the idle without a glow driver is not good, but it will just idle crazy slow with the driver on.