1998 wellcraft 240 SE 5.7 Prop question

[jws123]

I have a 1998 wellcraft 240 SE 5.7 currently running a 15x17 pitch aluminum prop boat goes ok but i am looking into a stainless prop to get a lil more performance maybe lil more speed or better out of the hole shot ect now i will admit my engine is a little tired i plan to rebuild next year but want to get 1 mroe season out of it. I can get to wot but never really pushed it dont wanna blow it up but When going stainless i saw some people drop a pitch? and dont get the same pitch in ss? just want to confirm what prop size/pitch i should get/try first as they are expensive


Also while i am here does anyone know normal compression for a merc 5.7? carbed 2barrel dont have the serial number on me at the moment but engine is new enough to have a serpentine belt not the old style

 

[alldodge]

Folks drop a pitch or 2 when going to 4 blade stainless. Going from 3 blade aluminum to 3 blade stainless, keep the same pitch and diameter. Doing this can gain a tad hole shot and WOT rpm because stainless doesn't flex like aluminum, and stainless blades are thinner, so less drag.

Best way to do prop changes is find a local prop shop that will sell you a prop and let you change at no cost, even if they cost more, the changes are worth the coin

 

[jws123]

Folks drop a pitch or 2 when going to 4 blade stainless. Going from 3 blade aluminum to 3 blade stainless, keep the same pitch and diameter. Doing this can gain a tad hole shot and WOT rpm because stainless doesn't flex like aluminum, and stainless blades are thinner, so less drag.

Best way to do prop changes is find a local prop shop that will sell you a prop and let you change at no cost, even if they cost more, the changes are worth the coin

ok thanks
and yea i have a 3 blade alum now plan to stay 3 blade i tried a 4 a while back boat didnt like it at all also places that let you try props are hard to come by anymore but i will ask a few local places.

 

[QBhoy]

If you can get to the full rated rpm (likely 4800)...you can afford to at least stick to the same pitch going to stainless.
Id like to know more details around what rpm and speed (gps) you are actually seeing.

All the best.

 

[jws123]

If you can get to the full rated rpm (likely 4800)...you can afford to at least stick to the same pitch going to stainless.
Id like to know more details around what rpm and speed (gps) you are actually seeing.

All the best.

il have to check it out when i put it in the water this season but last year 4200 rpm i was doin 25-30 depending upon wind load and waves

 

[QBhoy]

il have to check it out when i put it in the water this season but last year 4200 rpm i was doin 25-30 depending upon wind load and waves

Ok. If you mean 4200 when wot full throttle flat out...then that’s a bit low on the rpm side. I think you should be between 4400-4800 on that engine approx. I would have thought especially with That prop..you’d be higher up the range with your engine.

 

[jws123]

Ok. If you mean 4200 when wot full throttle flat out...then that’s a bit low on the rpm side. I think you should be between 4400-4800 on that engine approx. I would have thought especially with That prop..you’d be higher up the range with your engine.

wasn't wot i could of pushed it a little more as i said my engine is a little tired didnt want to blow it up lol but when i put it in the water this season il push it to WOT and see what it can do i plan to rebuild motor over winter but at least i have a general idea for prop size now going to try to find a used one first or borrow one.

 

[QBhoy]

Excellent. Unless she is blowing blue smoke and burning oil, she will be fine with a wee quick top end run at full throttle and trimmed well.
Your boat will be fairly heavy in weight and build but it’s a wellcraft after all. They don’t make slow boats usually. Likely a 15x17” is a standard Ally black max prop. These are great props for their price and often out perform the basic stainless props. All depends what you are after out your boat. I’m not going to bet money on it...but I have an incline you could maybe even turn a 19” prop too, depending on your gear ratio. Being home to think on your boat, a stainless prop might not show you a huge gain in any direction. It will look good and ultimately be more efficient, but don’t expect crazy gains in speed or acceleration, especially if you are keeping the same pitch.

If you want more speed...pay the money for a really good stainless prop of perhaps a higher pitch (if you can max out the rpm with the current pitch 17”) bit be prepared to suffer lesser acceleration. If you want acceleration or general all round...stick to what you have, go 4 blade (hate saying this. Not a fan) or get a big black max 16x16”.

 

[jws123]

Excellent. Unless she is blowing blue smoke and burning oil, she will be fine with a wee quick top end run at full throttle and trimmed well.
Your boat will be fairly heavy in weight and build but it’s a wellcraft after all. They don’t make slow boats usually. Likely a 15x17” is a standard Ally black max prop. These are great props for their price and often out perform the basic stainless props. All depends what you are after out your boat. I’m not going to bet money on it...but I have an incline you could maybe even turn a 19” prop too, depending on your gear ratio. Being home to think on your boat, a stainless prop might not show you a huge gain in any direction. It will look good and ultimately be more efficient, but don’t expect crazy gains in speed or acceleration, especially if you are keeping the same pitch.

If you want more speed...pay the money for a really good stainless prop of perhaps a higher pitch (if you can max out the rpm with the current pitch 17”) bit be prepared to suffer lesser acceleration. If you want acceleration or general all round...stick to what you have, go 4 blade (hate saying this. Not a fan) or get a big black max 16x16”.

Ok thanks guess il just have to mess with it a little but more and pay attention when i drop it back in the slip in 2 weeks before i buy anything it always seemed a little slow/sluggish to me on paper it says it should do 45 mph but i cant even touch that

i got the boat last year used it all summer it has no hour meter it does puff a little blue smoke burns a little nothin crazy guy i got it from didnt take care of it well going to do a compression and leak down test this week when i get it out of storage

 

[wellcraft-classic210]

Hi -- I don"t want to discourage you from getting all the performance you desire

And this may be old news--But in case you are not aware

-- A stainless prop is much harder and less forgiving if it hits something. As in it can transfer more strain to the drive and increases chances of drive damage.

--Aluminum can act more like a mechanical fuse to protect the drive.


I know I know -- Go stainless of Go Home

 

[jws123]

Hi -- I don"t want to discourage you from getting all the performance you desire

And this may be old news--But in case you are not aware

-- A stainless prop is much harder and less forgiving if it hits something. As in it can transfer more strain to the drive and increases chances of drive damage.

--Aluminum can act more like a mechanical fuse to protect the drive.


I know I know -- Go stainless of Go Home

i have yet to hit something knock wood hahah

 

[QBhoy]

Hi -- I don"t want to discourage you from getting all the performance you desire

And this may be old news--But in case you are not aware

-- A stainless prop is much harder and less forgiving if it hits something. As in it can transfer more strain to the drive and increases chances of drive damage.

--Aluminum can act more like a mechanical fuse to protect the drive.


I know I know -- Go stainless of Go Home

Hi

I hear this quite often these days. It’s honestly not the case anymore. That thinking is from the old days when stainless props were hard splined onto the shaft. This doesn’t generally happen these days. There are sacrificial hubs to prevent damage to the drive train. All but the most extreme props have these hubs nowadays.
Just my thought. Hope it helps.