Sundowner Outboard hydro

[RCBOATMANIAC]

Paul what do you run for a prop on your Sundowner? I have mine up and running, but I just can't seem to get it up on plane like it should, I have an Octura X440/3 prop on mine, but the engine loads up and stalls out before it can completely get up on plane. I was just wanting to find out what prop your boat runs on the best. So far the engine has been modified with an exhaust throttle, Tuned pipe, and the mods as per the blue prints, other than that it has the potiontial to get up and run just got to get the bugs worked out. Any help would be appreciated. Thanks Dave

 

[Duck899]

I'm not Paul.....but,The most sucessfull prop that I ran on a 3.5 o/b rigger was the Octura 1740/3.....

 

[Howard Welch Jr.]

I'm not Paul.....but,The most sucessfull prop that I ran on a 3.5 o/b rigger was the Octura 1740/3.....

hi i have run the sundowner and a grim outboard hydro for years the prop is a 1740/3 or 1742 or 1745 what engine are you runnin if a cmb or a mack you can run a 1745 you must set the boat up on the board with the skag off the outbaord the bottom of the ride pad and the bottom of the outboard must be level and rideing on the board the turn fin measure from the side of the tub to the fin arm or the piece of bar you used to conected the fin to the sponson measure the front of the the bar to the back and adjust the fin to measure the same you need a 1/16 of tow on each side of the sponsons or the boat will walk if you have any questions about the boat or if you wuold like to buy a kit i can get one for you .

thanks

junior

[email protected]

 

[RCBOATMANIAC]

I'm not Paul.....but,The most sucessfull prop that I ran on a 3.5 o/b rigger was the Octura 1740/3.....

hi i have run the sundowner and a grim outboard hydro for years the prop is a 1740/3 or 1742 or 1745 what engine are you runnin if a cmb or a mack you can run a 1745 you must set the boat up on the board with the skag off the outbaord the bottom of the ride pad and the bottom of the outboard must be level and rideing on the board the turn fin measure from the side of the tub to the fin arm or the piece of bar you used to conected the fin to the sponson measure the front of the the bar to the back and adjust the fin to measure the same you need a 1/16 of tow on each side of the sponsons or the boat will walk if you have any questions about the boat or if you wuold like to buy a kit i can get one for you .

thanks

junior

[email protected]

Thank you all for the replies and the info, so now it looks like I am going to have to make an order to Octura and get me a couple of props. At the moment the only props I have are Prather 215, 220 and Octura X440/2, X440/3, X637/3 no 1740's what so ever. For my 3.5 Tunnel hulls all I have ever ran on them is a Prather 215 and they all run very well on them plus I have never had the need to experiment since the last time I ever got to actually race was back in 1992 when I was Stationed in Long Beach, CA, and I raced at Legg Lake with most of the people like Joe Monohan and Lee Garcia and a few others. Now that I am living up here in Northern New York there isn't a whole lot of interest up here for boats let alone airplanes. The engine is a K&B 3.5cc engine so far the mods that have been done to the engine is I replaced the piston/sleeve with a piston/sleeve for a tuned pipe, Irwin Tuned Pipe, Prather 3.5cc Mod kit, and the mods shown on the blue prints. I'll check the other measurement that you have mentioned to see if it will make any difference. Thanks Dave

 

[RCBOATMANIAC]

Well I got my 1740/3 bladed prop all nicely balanced and polished to the boat out again for another test run, but all I can get it to do is a lot cavitation it tries to get up and nothing. As is all things in life I beleive that mother nature isn't going to give me much of a chance anymore this year to try and run my boat again. I did manage to get my big 11cc outboard outrigger up and running it almost looks like an over grown Sundowner hull the only down fall with it I don't thik that the turn fin is quite big enough for the boat because in the turns it pulls the right sponson out of the water. On my 3.5cc outrigger I had to use stainless steel to make the turn fin it is 1/16 inch thich would that have any thing to with the boat coming up on plane or not, if so what would be a good thichness for aluminum to use to make another one. Please let me know! Thanks Dave

 

[Howard Welch Jr.]

Well I got my 1740/3 bladed prop all nicely balanced and polished to the boat out again for another test run, but all I can get it to do is a lot cavitation it tries to get up and nothing. As is all things in life I beleive that mother nature isn't going to give me much of a chance anymore this year to try and run my boat again. I did manage to get my big 11cc outboard outrigger up and running it almost looks like an over grown Sundowner hull the only down fall with it I don't thik that the turn fin is quite big enough for the boat because in the turns it pulls the right sponson out of the water. On my 3.5cc outrigger I had to use stainless steel to make the turn fin it is 1/16 inch thich would that have any thing to with the boat coming up on plane or not, if so what would be a good thichness for aluminum to use to make another one. Please let me know! Thanks Dave

hi i am glad you have your prop now a turn fin it is .090 thick T 60/61 alum. at the bottom of the fin .250 up strait across the turn fin 22 degree bend from the top is a 22 degree bend from the base of your brase . this is for your 3.5 in some cases you will need to through the boat in a bet hard at about 1/2 to 3/4 throttle you will also need to take 600 grit sand paper and sand the bottom of your boat the idea is to sand the shine of what it will do is free the boat if you do this to all of your boats you will see a 3-5 mph increase like i said in my last reply give me your number i will call and help you it is hard for me to try to help you like this i have raced in dist. 19 on and of for 25 years if you would like give me a reply and i will give you joe monahans number and he has the kits or i can give you richards who has the same kits ether will be able to get you runnin if you would like oh did you trace the turn fin of the plans and on the plans should be on them you may need a better motor to make it run if you wont to email me your number my email is [email protected]

 

[Mike Hughes]

Are you launching it on plane? It will cavitate if you don't get it up on plane and just set it in the water.

Mike

 

[RCBOATMANIAC]

Are you launching it on plane? It will cavitate if you don't get it up on plane and just set it in the water.Mike

I have tried launching it by myself like I do with all my other outriggers, but I just can't get it to stay up on plane once the rear sponsons get swamped with water then it can't get back up. Then I had my son launch it holding it parallel with the water and send it out skipping it on the top of the water it tries to go, but all I can get it to do is cavitate. I adjusted the engine so the bottom of the lower leg is even with the center riding pad I was thinking of dropping it down a little to see if it stop the cavitation. I would like to get a better turn fin because it is hard to bend a fin and get the angle of the bends right without the proper equipment. Like I put in my last reply I made the fin out of 1/16 inch thick stainless which I think it has a little affect on it because of its weight. If this New York weather will hold out I'd like to get it out and try it again. Thanks for all the replies they are helpful. Dave

 

[Mike Hughes]

I run the center of the prop shaft at the bottom of the center sponson. This is where you problem is. Lower it down. The boat plains on that center sponson and there is not enough prop in the water.

Mike

 

[RCBOATMANIAC]

I run the center of the prop shaft at the bottom of the center sponson. This is where you problem is. Lower it down. The boat plains on that center sponson and there is not enough prop in the water.Mike

Thanks for the info I'll give that a try hopefully before the weather goes for the worse. I'd really like to see it run after all the work I put into the boat. It didn't turn out all the bad from what you can see in the pics That I have uploaded into my gallery. Dave