1979 Evinrude 140 venting at full trim at WOT........?

Theoutdoorsman · Oct 13, 2006

Hey guys/gals.......... I have noticed, prior to rebuilding, that I was venting (or the prop sounded like it was coming out of the water) before reaching my full trim limit at WOT. Would it be correct to assume that I need to lower the outboard on the transom to prevent this in the future? If so, what performance gains/losses, or other effects, should I expect to see? Also, does anyone have any experiences with Rampage props? Just looking for some pro's and con's. Thanks.............. ALAN

Texasmark · Oct 15, 2006

Re: 1979 Evinrude 140 venting at full trim at WOT........?

I wouldn't lower the engine for that reason only, period.

Most engines only have about 20 degrees of trim. There is a little tilt under it (that window) and a lot over it so that you can tilt the engine out of the water for storage or beaching.

Your transom angle really determines where you trim the prop outta da watta. Like on my last boat it was easy to trim out till the speed dropped off. If I kept it up the engine would ventilate. It had a slight tilt to the transom.

My current boat has 25 degrees of dead rist and my engine's trim poops out when the engine is only about 10 degrees above parallel with the hull. I'm running some pretty good numbers for WOT speed so it's not that big of a deal, but there's no doubt in my mind that if I would make up an adapter to drop that angle down to 15 to 20 degrees, I'd get some more top end.

Now you could talk to Kenny about getting a prop that holds tight with some of it out of the water and that might help you increase your speed when you would otherwise ventilate.

HTH

Mark

Theoutdoorsman · Oct 16, 2006

Re: 1979 Evinrude 140 venting at full trim at WOT........?

Texasmark..........Thanks for the heads up. I just really hate to buy another prop. I'm pretty happy with the one aleady have. Do you have any experience with these Rampage props? I'm curious if another brand prop, of identicle pitch, might be more suitable for me. I can't help but wonder how they compare to others, in terms of performance. Thanks again................. ALAN

Texasmark · Oct 16, 2006

Re: 1979 Evinrude 140 venting at full trim at WOT........?

Betcha Walleyehed knows. I agree that 6 props of the same dia and pitch will give you 6 different degrees of performance on the same boat.

On being happy with what you have, that's my current philosophy. I have $6k in this boat I bought last year and $500 in props trying to get it perfect................time to wake up to reality for me. :/

Mark

walleyehed · Oct 17, 2006

Re: 1979 Evinrude 140 venting at full trim at WOT........?

We gotta get you some other props to play with Mark....500$ ain't near enough yet....8)
The outdoorsman, if your prop is venting at full trim, you have a couple of choices...#1., lower the engine a hole, adding gearcase drag scrubbing off fuel economy and speed, with a loss in RPM, or, #2., Tell us what prop you have now, model, pitch, etc., what your current WOT is and I think we could lead you to a much higher tech prop than the out-dated Rampage.
It all depends on whether you want good, over-all performance, or just to be happy the boat moves.
Give us a bit more info and I think we can help ya out!

Theoutdoorsman · Oct 19, 2006

Re: 1979 Evinrude 140 venting at full trim at WOT........?

walleyehed said:
Tell us what prop you have now, model, pitch, etc., what your current WOT is and I think we could lead you to a much higher tech prop than the out-dated Rampage.
It all depends on whether you want good, over-all performance, or just to be happy the boat moves.
Give us a bit more info and I think we can help ya out!

Thanks a bunch walleyhead.......... The prop in question is a Rampage 13 1/4 X 20 RH. The number on the prop is 201003. I guess, really, I'm satisfied with the overall performance of the prop. But I would like to know I'm getting the most bang for the buck just like anyone else. If we're talking about significant differences between performance when comparing the different props, I'm certainly interested. But if only gaining 2-3 MPH or so, I would rather spend the money elsewhere. Now, on the other hand, if we're talking differences in speed being 8-10 MPH on top end, we really need to talk..........d

....... Currently, I am in the middle of breaking in my newly rebuilt powerhead, so giving you an accurate rpm reading at WOT isn't possible yet. However, before the rebuild, I could turn the prop at about 5600 - 5700 rpm's, depending on my load, if this helps. I'll get a more accurate reading for you at a later date. But given this cenario, what would you recommend? Thanks a bunch for your time!!...................... ALAN

Texasmark · Oct 19, 2006

Re: 1979 Evinrude 140 venting at full trim at WOT........?

Hey Kenny, actually I lied. :% I have bought 2 SS and 1 alum since buying the boat.....caught them on sale.

Mark

walleyehed · Oct 19, 2006

Re: 1979 Evinrude 140 venting at full trim at WOT........?

The Rampage you have is a 3-bld?

Theoutdoorsman · Oct 20, 2006

Re: 1979 Evinrude 140 venting at full trim at WOT........?

walleyehed....... yes sir, it is a 3 blade.

walleyehed · Oct 20, 2006

Re: 1979 Evinrude 140 venting at full trim at WOT........?

I'd be looking for a 13.5X20 Raker...If you can get your hands on a good used one, you'll see the difference real quick.
5600 really isn't enough on that engine...5800 would be best, but the Raker will lift quite a bit.
I found that a 20P Raker on my V6 runs higher RPM than several of the 19's I have but it's because of the lift, and how my boat responded to that lift.
I went with a jackplate that added too much setback and now I can't run the bow-lifters without porpoising, so I will be going back to my shorter plate.
Another prop that would likely give better over-all performance would be a Turbo1 intermediate in a 19.
Just depends what you're looking for. 2-3mph is an impressive gain for any rig....it all adds up to better fuel economy.

biggy boy · Oct 23, 2006

Re: 1979 Evinrude 140 venting at full trim at WOT........?

walleyehed said:
I went with a jackplate that added too much setback and now I can't run the bow-lifters without porpoising, so I will be going back to my shorter plate.

Hi Kenny
What lenth setback were you running and what will be the new lenth, what hp motor and on what type of boat?

Thanks
Glen

walleyehed · Oct 23, 2006

Re: 1979 Evinrude 140 venting at full trim at WOT........?

Had about 7-1/2" with 2" spacers...played with it without the 2" spacers and ran so-so.
last plate (previous) was 4" home-made.
Boat is 18ft aluminum deep-V with a 200 'Rude.
Runs best with the 4" plate hands down.
I'm going to install a Bob's 4-in-one convertable plate next...it's the only answer I see to set-up for the props I want to run.

Theoutdoorsman · Oct 29, 2006

Re: 1979 Evinrude 140 venting at full trim at WOT........?

Thanks walleyehed........ The info was much appreciated!!!! I'll get back with you on this a little bit later, as the breakin is almost complete. I did run it at WOT, last outing, for about 20 seconds though. Looks like 5700 RPM's on that Rampage prop was all I could manage in that short time frame. A handheld GPS unit is in route to my hands in the next few days. I'll get back in touch with you soon......... Thanks again................ALAN

walleyehed · Oct 29, 2006

Re: 1979 Evinrude 140 venting at full trim at WOT........?

we'll be here!

Theoutdoorsman · Nov 2, 2006

Re: 1979 Evinrude 140 venting at full trim at WOT........?

Walleyehed......... Will a CMC PT-130 hydrolic jack plate withstand the power exerted by this outboard, or would you recommend something else?

Crownie2 · Nov 9, 2006

Re: 1979 Evinrude 140 venting at full trim at WOT........?

Theoutdoorsman said:
Walleyehed......... Will a CMC PT-130 hydrolic jack plate withstand the power exerted by this outboard, or would you recommend something else?

The PT-130 is a trim and tilt unit only. I think you would want something like the PL-65 instead...(unless you don't have power trim now!)

Also the manual version of the PL-65 is very nice.

walleyehed · Nov 11, 2006

Re: 1979 Evinrude 140 venting at full trim at WOT........?

I swear I posted a response to this question, The outdoorsman, but somehow it didn't make the board?
I agree with Crownie on the other choice unless you don't have PT&T.
The Bob's 4-in-1 is an excellent option as well....if you "have" PT&T.

WTPhantom309 · Nov 11, 2006

Re: 1979 Evinrude 140 venting at full trim at WOT........?

Outdoorsman, are you talkin about the motor in ur picture by your name? I know its a bit off topic but it looks way different than my 77-140HP but from the way its sounding acts the same way, mine vents at 3/4 trim wot.

Derek

1979 Evinrude 140 venting at full trim at WOT........?

Senior Chief Petty Officer

Supreme Mariner

Senior Chief Petty Officer

Supreme Mariner

Admiral

Senior Chief Petty Officer

Supreme Mariner

Admiral

Senior Chief Petty Officer

Admiral

Seaman

Admiral

Senior Chief Petty Officer

Admiral

Senior Chief Petty Officer

Petty Officer 1st Class

Admiral

Seaman