J232

Hello again

Well I tried out the boat for the 1st time tonight, Now I confused myself.... The motor runs clockwise.... The prop turns counter clockwise.... The prop nut tightens clockwise. My problem is the prop keeps comming loose. Do I need a different prop and to run the motor counter clockwise?? If the motor is run counter clockwise and the prop turns clockwise and the nut tightens clockwise it would stay tight right? So what do I have to do to fix this problem? I still havent been able to try my boat out, it hasent been a very good experience for my 1st nitro boat. I still really want to get it out tho... []

Thanks

John

J232

actually its not the prop nut, the prop key was loose, so I fixed that but it still just revs... It only moves at idle... If you turn it revs and stops. I dont know what the prob is, I dont think the prop is slipping on the shaft. I tried trim up and down andI lifted the motor and dropped it same thing. I think im going to pick up a new prop shaft.

MY centerline for the prop is at the bottom on one of the sides... its not centered in the actual tunnel (middle) should it be? Also do I have to whip this thing a 1/2 throtle to drive it? I wasnt aware that if you slow down it will cavitate. Yet if I go slow its fine but it wont speed up just make a bunch of noise.

Ron Olson

My Feedback: (1)

The problem sounds like it my just be your throttle cable. Send a pic of that. It has to be hooked up on the motor block usually with a clamp. Even if you have that, sometimes those loosen. Check at the radio box too to see if the cable tube is attached there.
If you do have problems with the prop nut coming loose, add a piece of larger fuel line between the prop and nut. I haven't lost a prop yet on any of my boats by doing this.

J232

Its not the cable, I can give it full tilt it will hit peak rpm but the boat dosent move. The boat only moves at low rpm when I try to hit the gas it seems like something lets go and it just revs up. I checked the prop shaft dog and I couldnt move it but I guess that dosent mean the 7.5 cant. Its sorta like a clutch that lets go and when you let it rev back down it engages and jump and takes off again untill you give it gas again... Even at idle and its moving fine, I turn fast and it stops again. Like the prop stops

My cable is clamped to the block, this is a driveline or a cavatate problem

Ron Olson

My Feedback: (1)

Is the flex cable worn on one or both ends? Check the drive and the power take-off (back plate) on the motor too for wear.
The prop centerline should be just slightly higher than the bottom of your sponsons, usually around 1/16".
I am assuming that you have a good knowledge of outboards or not? How would you consider yourself? This will give me an idea of ways to help you out.

J232

well I am about 2 months old in the nitro thing, I am a mechanic so it helps. I have had this outboard for a month now. So im new, I understand the engine, but like anything it will take me a bit to learn some stuff, the pto case and pto shaft is new, I will check the prop shaft hole though, never really though of that. I get a dry bearing vibration good enough to stop the motor too. Only happens if it sees water though. I am sure it in the bottom area, if not then its my new pto bearings

J232

Heres some pics

The squeal noise I think is coming from that fat washer that goes on the end of the PTO shaft, its is loose on there, I can make it fall off by shaking the motor.

YOu can see in the pics that my prop is below the whole hull, this is with the trim all the way down... This is as high as I can set my motor with the mount setup that is on there. I also discovered that my prop dog is slipping on the shaft, It takes a bit to make it do it but any slip cant be good, flex cable and where the drive from are all good.

Prop is a octura 1450

Ron Olson

My Feedback: (1)

If you're getting a squeal, that a sign of not enough grease on the flex cable. If it falls out that easily you night have to replace the teflon liner tube inside the lower unit.

J232

ok, ya the squeal stalls the engine at idle... I will lube the flexshaft good. It dosent falls out of the tube it has to be pulled out also. Can you tell in those pics if I have to have my prop up higher or trim it higher? I fixed the slipping prop dog... I was thinking of taking the boat out to a local river tonight to see if it will take some gas now... BTW do I need that fat washer on the bottom of the motor where the pto shaft comes out of the bearing??

Ron Olson

My Feedback: (1)

Yes, that is very important. It helps to control slop plus works as a bearing surface. If you can't find a K&B washer for that, Prather, Octura and Aeromarine among others use the same basic thing on their driveline so some Hobby Shops carry them.
Man, I hope that your rivers aren't like the ones here in Michigan! I haven't seen them this high since some pix that my Dad had back when he was a kid. I went by my practice pond on the way home from work a little while ago and it has to be easily 3-1/2 higher than usual.

J232

ok I will put that back on, I'll try to make it fit tight. Well the river im talking about does have strong current but there are areas that are shallow 2 or 3 feet with no current. Im not sure if I will take it out. I want to see if I have the bugs worked out. I mig welded the prop dog to the prop shaft "hehe" I drilled 4 holes in the dog and tacked it to the shaft then made it all nice. I will still pick up a new shaft.

How is the octura 1450 prop? I might just do some tuning tonight, its really boggy still.... I will have to play with the trim too I think or add some weights but im more worried about getting the boat stable 1st (drivline/motor tunning) 1st

Ron Olson

My Feedback: (1)

I hope that the 1450 has been reworked as it is a lifting prop meaning that at speed or sooner the rear end will lift up and then things get really interesting, your boat will turn into a sub! For less hassle and tuning in the boat I'd recommend from Octura an X447, X448, X450 or a X646. From Prather a 230 or 235.
Please watch out for currents, they run faster than they look, I know from personal experience! My DPI 7.5 tunnel broke an antenna wire and my boat jumped over a hill from our pond into the connecting river. My little 2-man inflatable stroke* boat wasn't up to the job of battling the current going back upstream.



*Stroke boat: Stroke! Stoke! A rowboat.

J232

hehe I know current... I had a "stroke boat I put in a lake and ended up 5 miles down on the shore, ended up walking back [&o]

I bought this lapcat used and this is the prop it had on it, I wonder why that prop is on it... It is polished and is like a razor.

I just finished putting it all back together, I filled the flex shaft full of lubriplate, a synthetic white spray grease. I wont know if the squeal is gone till it sees water. That big washer on the pto shaft I "bent a bit to make a nice tight fit when its on, I had to press it on so it should be good. I decided not to go out tonight, I want to but im beat. I started up the boat and ran it for a bit... It runs ok its a bit rich I think... I got a brand new carb off ebay but it wasnt the right one, it was for a .40 so I took everything off it but the barrel and the body... Used all the new needles and stuff in my carb. Anyways im going to run to the lake tomorrow after work and see if its working yet. Im not wild on the idea of jumping in a smelly river if I had too lol

Thanks for the help and I will let you know the results, I will also pick up a new prop.... Is there any places (boat hobbyshops) that accept paypal, I ask because I have cash sitting in my paypal account and nothing looks good on ebay right now "hehe"

J232

is this 1450 prop going to give me cavitating problems

Ron Olson

My Feedback: (1)

It could very well be the source of your problems. Racers modify the props to reduce the lift in the prop but one off the shelf isn't good at all on anything but an outrigger hydro.

J232

I see, so I should grab one of the ones you mentioned and sharpen it polish and balance it? I assume when you say modify you mean bend?

Ron Olson

My Feedback: (1)

Yes. Props can be bent and/or cut to different shapes for performance.

J232

how do you sharpen and polish a prop? dremel tool?

Ron Olson

My Feedback: (1)

I use a file first to get off any extra molding flash on it and to sharpen the leading edge before hitting it with the Dremel. Wrk on the backside only, never on the face.
www.funrcboats.com has a nice article in their site to guide you through the process.

TERBObob

My Feedback: (21)

I realize that this "might" sound a little off , but , are you by chance giving her a good toss when you put her in the water ?

J232

Actually, no... I found out today that I need to throw it hard when I launch it to get on it plane when it hits the water... I have been doing a 1 hand drop toss thing. Not near a throw... I did get a new prop today, only one I could find close is a 240 prather... not sure if it will work.

Ron Olson

My Feedback: (1)

That's too big. The Prather 235 is at the top end of their choices for your boat.
Giving the boat a level toss to the water does 3 things for me when launching. First, it'll keep the boat from flipping over backwards, it puts less stress on the driveline, and last, if it's throws a roostertail you'll stay dryer.

J232

well that sucks, what kind of problems will I have with the 240.....

Ron Olson

My Feedback: (1)

You'll have to run it rich to keep from overheating the motor and you won't get the speed but one thing, you'll find out if it was the other prop giving you the problems.

TERBObob

My Feedback: (21)

With the 240 , you could tinker with it also . And of course , before popping it on , make sure you make her sharp as heck and balance it out .