Engine Set Up On Toon

[OBJ]

Need some advice. I got a 20' toon with an 89' J/Rude as motive power. If Memory serves, the prop is a 17" pitch....not real sure about that but I can check...it's SS. The engine came with a whale tail (StingRay brand) so I left it on.<br /><br />I have the engine mounted one hole up which puts the anti-cav plate about 3" below the center line of the toons. Toons are 21" diameter.<br /><br />The engine struggles to make 4500rpm (as I posted, not sure of the prop pitch)and I usually just keep it around 3600 > 4000 rpm. Trim helps a little but not much.<br /><br />First outting on the river I noticed that whale tail was really under the water and not on top once under way....think I'm going to lose it and see what difference that makes.<br /><br />I guess the real question is about the engine set up on the transom. Not real familiar with this type of set up and would like any suggestions and ideas. As far as the enigne is concerned, it's in top shape and pulled 5k on the dyno without breathing hard.<br /><br />Thanks for any advice.<br /><br />Jim

 

[rickdb1boat]

Re: Engine Set Up On Toon

Hey OBJ<br /><br />On my toon, the cav. plate it just above(2"-3") the bottom of the logs. You don't say what size motor you're running, but I'm betting unless it huge, the prop pitch is way to high. I'm running a 14 X 11" on my 70 HP rude and I peg right at 6000 with 2 on board. I had a plate on mine too, but took it off some time back. It really didn't help or hurt anything for that matter. Speed was about the same. I don't know that the prop ever rides on top like "Normal" boats do. Then again, I've never really looked. You could try raising it a little more. You will know real quick on a toon if it's too much. Can you turn at full throttle right now without blowing out? Usually, that's the first clue. BTW-Shoot me an E-mail if you would. Having some issues with the rude that I'd like your opinion on....rickdb1@earthlink.net<br /><br />One other thing. With that small diameter of logs, you have to realize that your prop is going to be farther underwater than someone who has 23" logs with the same motor. Best to look at it when it's sitting in the water and see how far the plate is submerged. You may be mounted the same distance as I am from the bottom of the log, but because mine may have more flotation, the plate and prop will be higher than yours...food for thought.....

 

[OBJ]

Re: Engine Set Up On Toon

Thanks for the ideas Rick. Ya' know, never gave it a thought about the logs letting the gear case set lower in the water.....and I will try a lower pitch prop. Ain't so much worried about a lot of speed as I am about lugging the engine. Might get out today....if the darn rain would stop.....wife wants to fish...... <br /><br />We'll keep ya' up to date on what we do. By the way, I got an 89' 50hp J/Rude on the back of it. Don't blow out at WOT unless I trim it up way far.....which just put the light on in the head.....I really have to trim it out to get it to blow.....maybe she is to deep....hmmmm.

 

[rickdb1boat]

Re: Engine Set Up On Toon

I'm thinkin' the 13 X 11" would suit your needs just fine. Got to get those revs up.....Hope you make it to the water...

 

[steelespike]

Re: Engine Set Up On Toon

OBJ I have a 18 ft Starcraft, 23 inch logs, with a 87 50 hp.Evinrude.<br /> Unfortunately I don't know what pitch I'm running but 17 is definately too high. as I recall mine turns about 5,200 rpm.<br />I usually cruise at about 4,000.As Rick suggests<br />11 or 12 inch pitch should do it.Keep raising the motor till blowout becomes a problem.<br /> A toon doesn't plane so speed is not one of its strong points.Under ideal conditions you will probably get about 18-20 mph.And at that speed you'll use a lot of gas.Run about 4,000 rpm and you won't lose that much speed and save pretty good on gas.<br /> By the way Rick If your 70 is prior to 86 it developes its power at 5,000 rpm.I'm no expert<br />but at 6,000 you may be pressing your luck a little.

 

[rickdb1boat]

Re: Engine Set Up On Toon

Hi Steelespike, it's a 91' model....

 

[OBJ]

Re: Engine Set Up On Toon

I was out looking at it this evening....between rain squalls....and I think I can raise it at least two holes. Glad it's only a two cylinder.... . I'll also give the lower pitch a shot also.<br /><br />Thanks to both of you gents for your help. I'll let ya's know how it goes.