Jump to content
smboudreaux

98 20LT 200 vmax, missing top end spend, where to start?

Recommended Posts

I recently picked up a 98 20LT powered by a 98 200 vmax.  In comparison to guys with similar setups here I seem to be missing quite a bit of top end.  As of now it tops out 43 at 5800.  Cruises about 30 at 4000.  Currently running a 4 blade prop. Not sure the make or model.  The only stamps on the back are H 26 28.  6" jack plate.  Previously the motor was possibly set to low.  From keel to prop shaft was 5".   I raised the motor to keel to prop 3.5" today but I have not had a chance to run it yet.  Another forum member pointed out that I will not a gain that large from motor height.    So my question is where do I start first?  prop shop?  I feel like if the motor is making the power to turn up the rpms it should be mechanically sound.  thanks fellas

Share this post


Link to post
Share on other sites

You don't want to turn anymore rpm's.  I'm getting 54 in my 21 RF with a 200hp 21 pitch prop and that's on the slower side. I'd figure out what prop you have before anything else.

Share this post


Link to post
Share on other sites

Not enough prop, 5400 is the wot rpm on that motor. Those hulls are bow heavy so a bow lifting prop should help. You should contact Funky Monkey on this forum, he is the prop god on Pathfinder, hewes, and maverick hulls and works at Power Tech Props in Shreveport, La. He is a tremendous resource on this forum.👌

Share this post


Link to post
Share on other sites

Sounds like you need to go up a bigger pitch to bring down the RPM's a bit. That will give you a bit more speed. If you want top end speed then I say switch to a 3 blade instead of the 4. You will have less of a hole shot and you will have to just trim down on the turns cause the 3 will not have the bite of the 4.

Share this post


Link to post
Share on other sites
On 8/10/2018 at 8:19 PM, smboudreaux said:

I recently picked up a 98 20LT powered by a 98 200 vmax.  In comparison to guys with similar setups here I seem to be missing quite a bit of top end.  As of now it tops out 43 at 5800.  Cruises about 30 at 4000.  Currently running a 4 blade prop. Not sure the make or model.  The only stamps on the back are H 26 28.  6" jack plate.  Previously the motor was possibly set to low.  From keel to prop shaft was 5".   I raised the motor to keel to prop 3.5" today but I have not had a chance to run it yet.  Another forum member pointed out that I will not a gain that large from motor height.    So my question is where do I start first?  prop shop?  I feel like if the motor is making the power to turn up the rpms it should be mechanically sound.  thanks fellas

Call the Funky Monkey at Power Tech...Marcus....he'll give you a hand.

 

dc

 

Share this post


Link to post
Share on other sites

alright so it turns out I had a worn out mercury prop on it.  went by the local boat shop on the set me up with solas hr4 21 pitch.  huge difference.  now she cruises at 40-41 @ 4000 rpm and  WOT is 50 @5100 rpm.  the motor was set to high.  I couldn't trim much before the would blow out so it was still bow heavy.  still plan on getting a power tech 3 blade to see how it does

Share this post


Link to post
Share on other sites

That’s a good start. How was the first prop wore out? Slipping hub ? Ground down blades? Was it in obvious disrepair? Or was it just the wrong pitch?

Share this post


Link to post
Share on other sites

This is my first go round with props.  I'm not really sure.   They said it's been reworked to death and the way it's bent right now it's sole purpose in life was to get on top in no water and in a hurry.  Which was true.   It would get up in no time.   

20180815_075245.jpg

20180815_075241.jpg

20180815_075255.jpg

Share this post


Link to post
Share on other sites

Yep it looks pretty thin. Also looks like it was never a high end prop to start with.. glad you got you problem on the run. 

Share this post


Link to post
Share on other sites
On 8/15/2018 at 6:16 AM, smboudreaux said:

alright so it turns out I had a worn out mercury prop on it.  went by the local boat shop on the set me up with solas hr4 21 pitch.  huge difference.  now she cruises at 40-41 @ 4000 rpm and  WOT is 50 @5100 rpm.  the motor was set to high.  I couldn't trim much before the would blow out so it was still bow heavy.  still plan on getting a power tech 3 blade to see how it does

Can you gain any more rpm's/speed by trimming up higher?

Share this post


Link to post
Share on other sites

Some, not much.   Dropped the motor an inch.  Took it out this weekend.  Still getting about 50 mph @ 5k rpm with.  Still need to come down on the motor some.  Blows out in turns.  The prop has tons of lift.  I think the 21 blade is just too much for my setup.  Funky monkey recommended a 21 3 blade or 19 4 blade.  I'll be ordering one of those shortly

Share this post


Link to post
Share on other sites

Get a 21 tempest 3 blade. I saw 53 consistently and had the same setup with you (Had a different prop). Tempest will have good grip and have lots of bow lift. Honestly not a fan of powertech props. The OFX is a slow prop and is only good for grip and stern lift IMO. Their RKR isn't a bad design but you rarely see them. 

Share this post


Link to post
Share on other sites
3 hours ago, smboudreaux said:

Some, not much.   Dropped the motor an inch.  Took it out this weekend.  Still getting about 50 mph @ 5k rpm with.  Still need to come down on the motor some.  Blows out in turns.  The prop has tons of lift.  I think the 21 blade is just too much for my setup.  Funky monkey recommended a 21 3 blade or 19 4 blade.  I'll be ordering one of those shortly

You just saved me from buying the wrong prop. I was thinking about trying the same solas prop on my 21 redfisher that's powered with a 200hp vmax. 

Share this post


Link to post
Share on other sites

I must be missing something?  I understand that you are trying to get it propped right but why are you raising and lowering the motor so much?  I thought I read you have a jackplate.  I would think a motor mounted low on a jackplate would get you running good for most conditions.  Sorry if I missed something.

Share this post


Link to post
Share on other sites
3 hours ago, linesider 159 said:

Get a 21 tempest 3 blade. I saw 53 consistently and had the same setup with you (Had a different prop). Tempest will have good grip and have lots of bow lift. Honestly not a fan of powertech props. The OFX is a slow prop and is only good for grip and stern lift IMO. Their RKR isn't a bad design but you rarely see them. 

 I like the tempest prop too. I do not say too much about Mercury props because a lot of people are loyal to power tech here. But tempest plus is a great prop for bay boat set ups. It will run high and hold its grip high in the water. Mercury enertia is also a pretty good prop on a bay boat. 

Share this post


Link to post
Share on other sites
On ‎8‎/‎20‎/‎2018 at 2:54 PM, mulligan said:

I must be missing something?  I understand that you are trying to get it propped right but why are you raising and lowering the motor so much?  I thought I read you have a jackplate.  I would think a motor mounted low on a jackplate would get you running good for most conditions.  Sorry if I missed something.

when I started trouble shooting my problems I looked into my motor height.  using the props shaft the keel method I was 1'5" low so I raised the motor up.  I do have a jack plate.  I'm pretty much back to the height I started at. 

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×