Funny engine revs on new opti

[SteveO]

Just got a new rig. running 135 opti on a 17 foot lund. The tach is reading 6400 at wot, and the engine is whiney if that is right. First boat, so I am abit scared. It sounds like my racing bike. I have 13 pitch ss. on it prop. Any ideas thanks...only geting like 35 mph on gps...Steve

[Brad B]

13 pitch on a 135 opti? 6400 rpms? IMHO, your running dangerously high rpm's. Try a 19 or 21 and keep your rpm's below 5600.

I'm running a 21 on my 150 opti on a 17' yarcraft and pulling about 5200 rpm's at WOT. Top speed is about 50 mph.

Mercury's website should have the recommended rpm range. A decent lund dealer would be able to tell you what size prop to get.

[Steve]

I really do not have access to a dealer until later this summer. Got a great price on the prop from ebay, so would like to utilize it. It is in the 2nd hole, just looked. Would moving it up a hole or two help. Has a nice hole shot though...STeve

[scarey thought]

run it till the enjine blows then you can buy a new prop and motor to go with it. i am running a 19 pitch on a 90 horse

[Steve]

So you think I should switch up to highe pitch prop? Would that get rid of the noise, and help with the speed? I would rather try and adjust motor height or trim rather than dole out another 85.oo bucks for a ss prop. Any other insight? I don't think I will blow the motor , it is really new...Steve

[Ric]

You are way under propped. I wouldn't run that small a prop on that motor if I were paid to take it. Do yourself a favor and get about 19 pitch.

[Ric]

By all means switch, and do it soon. You can and will blow the motor, and it won't be covered under warranty if your running 6400 rpm's. BTW, 85 bucks sounds super cheap for a SST prop.

[MNUser]

Dangerous! Not such a good deal when the engine goes....change to a 19 or 21 pitch. 13 is not offering enough resistance.

I run a 19 on a 90 Merc and it runs 5400 @ 42 MPH. Runs perfect. Have thought about stainless but not sure if I want to shell out the cash.

[Steve]

When you are sayin I am not gettin enough resistance are there other solutions? could i bend the blades or run the motor trim down instead of all the way up? Can I modify or do I need to buy? Cool ring to the jingle...Steve

[Ric]

You need a new prop. Period, end of story.

[Shep]

Tight Lines All,

Shep

[Shep]

[Detroiter]

Bend the blades??????????????????

That's like saying that my 8 cylinder is running rough so I am going to file down the pistons.

There is no other answer than to get a new prop. Put the one that you have on ebay. What you think was a good deal is going to destroy your motor - if it hasn't already. Never run that Merc again with that prop.

Don't try to take a cheap way out on this. You WILL be sorry.

[Shep]

nevermind.

Tight Lines All,

Shep

[perchjerker]

Sounds like a troll to me, Shep.

[Cliffy Kleven]

You'd whine too if you were propped wrong and over-revving by a thousand. Is there a rev limitation device on that engine? If so, it ain't working. Or something?

[King Withem]

Lotsa trollin happening lately.

[tom]

Some BS going on here boys. The Optimax has an RPM limiter that will not let the RPM get up to 6300----Hmmmmph

[Workin]

Hey guys I think old Steve is pulling our leggs. 13 pitch ss prop for a 135 opti even used would be more than $85, and bend the blades! I kind of think anybody that silly wouldn't be able to find this sight.;)

[Fishnmagician]

SteveO, better yet, why not try shaving down the blades a little, maybe you can get 6500-6600rpms out of it.

[FJH1]

PJ, I completely agree.

Best Regards,

FJH

[T-Mac]

He did get quite a few bites on his trolling pattern, 'tho.
:)

[Shep]

You caught it PJ.

Completely empty, and 5 gals of fuel and I just tick the rev limiter. I can tell you it ain't anywhere near 6400! His trolling pass caught a couple shorts, it appears! hehehe

Tight Lines All,

Shep

[FshnFnatic]

What ya need is a left hand rotation prop!! FNF

[Bill]

sounds like prop to small I have 90 merc with 17 pitch alum get 41 gps on a tp175cs alumacraft

[hgmd]

Steve-
I really think you need to incorportate the assistance of a dealer. First off, the propeller that you have sounds to be terribly under pitched. You are not doing any justice for your motor with it. The most important factor in proping a boat is using the correct pitch. If you do not have the correct pitch, your boat will not perform well at all. You will also damage your motor. This also would not be warrantable as your motor is not propped correctly. The motor would fail due to your error and not due to defect of the product. Just because a prop fits on your propshaft, and the price is right does not make it the correct prop for you. Didn't the dealer provide you with a propeller? What pitch was that, if he did provide you with one?

Also, the Optimax motor has a guardian mode. You should not be able to reach the RPM's you are stating. You should have your guage checked out. Are you using standard analog guages or SmartCraft guages?

[SteveO]

Hey guys, I guess I look a bit foolish. I was just trying to get some info and just get made fun of. I am new to boats, and knew something was not right. I am looking at 23 pitch prop know that I can trade even up for, so That should solve my problems...HOpefully you guys will be a bit more gentle in the future with your fellow boaters...STeve

[Jim Carroll]

Steve, Post #25 gives some good advice. If you do not have access to a dealer, tell us your exact setup (boat, motor, and mounting hole of the motor) and likely someone here on the board has the same setup and can help you. I doubt a 23 pitch will work for you, it's too much. Also your Opti isn't capable of turning the RPM's you mention because of the Rev Limiter. You will hear a loud horn if you over rev it. You should check your tach. JC

[Mech]

Your driving us crazy with all this " can't I just bend it" and are you sure I need a new prop, I hate to judge but Please listen to what is being told to you.

[Shep]

Actually, if the boat is a 1700 Angler SS, that 23P prop may be just fine. I have that boat and motor, and am running a 23P LaserII. Fully loaded, I turning 5300-5400 at 51-52 GPS. Empty, I just start ticking the rev limiter. But that limit is nowhere near 6400. Still confused on the 13P prop. Did a dealer put that on there?

Sorry for my rude behavior, but it sure looked like a setup to me.

Tight Lines All,

Shep

[FshnFnatic]

I think that perhaps there were 2 Steves and that is where the shananigans started.? Steve (guest user) SteveO (guest user). Sorry SteveO for the silly reply just thought someone was trying to be funny. What ever you do... QUIT RUNNING THE MOTOR AT THOSE REVS:o :o
The motor has a computer on it that registers EVERYTHING you do and how the motor was ran.
Take the rig back to your dealer along with a brick to slap him alongside the head or better yet just find a different dealer that doesn't have their head stuck somewhere and have them work with you. Where are you from? I'm sure that someone on here can recommend a dealer where ever you are located. What boat do you have it on?
I had a 2000 1775 Pro-V with a 150 Opti. I liked the 21 pitch Hi-five. Many on here seem to push the Tempest plus 21 pitch. I never tried one as I sold the boat before I got to that step. Find a dealer that will let you test out several differant props before you make your decision. A good dealer will get you headed in the right direction and a 13 pitch prop is FAR from it. Good luck with your adventure. FNF

[SteveO]

Hello guys, with the 23 I was able to improve performance a bit 38gps at 4700 rpms. HOwever the hole shot was weak. The noise is gone. Can I expect better or is this rig topped out. Thanks,Stevey

[Cliffy Kleven]

19 should be just right, based on what you have told us.

[Dave in Mpls]

You are over-propped (assuming your tach is right, which it isn't, because you can't spin a 135 OptiMax to 6400 RPMs) In any case, I think you need to get to a 19-21" pitch prop. First, have your tach calibrated. You are trying to reach 5500 RPM with just yourself and a light load. No offense, but who is your dealer???

[T-Mac]

Actually.......It has been my experience.....when you gently work, slowly up to the rev-limiter you get a miss. When you hit it "hard", like "blowing out" on a hard turn...she shuts down.

Kind of that way on all the things I have over-revved.

On Mercruiser I/0 you start getting a miss. Then I never went further.

On Yamaha, Johnson and Evinrude, which I have over-revved...they just shut down.
You simply cannot go past the rev-limiter on anything I have I done it to.
I even did it to a Ford truck when I was bookin along in the middle of Montana with the speedo buried.

I don't recall a horn.....But I don't hear well when I am puckered up tight.

:)

[SteveO]

Hello thought I would clearify something if it makes a difference. This motor is new, but the boat is old. It is an early seventies fibeglass trihull. Would that make a difference in prop? Other than the nasty color it is a great rig....SteveO

[T-Mac]

No. But... it sure explains why the dealer was off so far on his guess at what prop to try.

After all the information exchanged back and forth in this thread, it appears that a 19 pitch is what you probably should use.