Factory prop sizing question

[bluewaterboater]

I have a 1999 Sea Ray 190 Signature Bow rider and lately I've been having some issues with over reving and popping sounds. I posted my motor issues in another thread and have been getting great help. After a tune up and some other positive results the prop size was mentioned in the thread. I bought the boat a few months ago and I'm still getting to know it I also thought it had the factory prop. After some research I am now confused.

This is what I have: 4.3l EFI 210hp with Alpha 1 drive gear ratio 1:81 with a Vengance SS prop 4816318 21p

According to the Sea Ray site my boat should have a 1:62 Alpha 1 with a 14 x 19 SS Vengance.

It shows that the NON EFI 190hp version should have a 1:81 Alpha 1 with a 14 x 23 AL - Black Max.

My boat has 169 hours on it. Is it possible that they made different gear ratios or did someone change my outdrive? Does it matter? What prop should I use?

Right now I can go over 4800 WOT and my tach goes crazy bouncing all over the place and I get a popping noise in the engine until I throttle back. I have more throttle available after 4800 rpms.

Thanks for any help you can give!

 

[jestor68]

Re: Factory prop sizing question

It's likely that the factory stuck whatever drive they had available at the moment your boat came down the assembly line.


If you purchased the boat from a dealer, they should help you select the correct prop; which would usually be the next step higher in pitch to start.

 

[steelespike]

Re: Factory prop sizing question

From your description and from the usual prop sizes you see on here for a 4.3 I think a 23" stainless mercruiser prop.
should lower rpm by 300 to 400.By sticking with same brand same model you increase the odds of a successful improvement.
If the 23 proves too much for water sports the 21 should work.

 

[bluewaterboater]

Re: Factory prop sizing question

From your description and from the usual prop sizes you see on here for a 4.3 I think a 23" stainless mercruiser prop.
should lower rpm by 300 to 400.By sticking with same brand same model you increase the odds of a successful improvement.
If the 23 proves too much for water sports the 21 should work.

Thanks, I have a 21p on there now and plan on keeping it for watersports. The popping sound is happing with the 21 and maybe the advice from jestor68 is correct and I am hitting the rev limitor. If thats the case then at least I understand what is going on because I thought there was a problem with my engine. I will get a 23p and try it so I can go full out and stay within WOT.

 

[bluewaterboater]

Re: Factory prop sizing question

It's likely that the factory stuck whatever drive they had available at the moment your boat came down the assembly line.

It 's supposed to have the 1.61 gear ratio, but it has what it has.

The sound you are hearing is most likely your engine hitting the rev limiter, which will interrupt the ignition rapidly ( off and on) to keep the engine from going past the set limit. The corrective action is to simply put on a prop with more pitch.

If you purchased the boat from a dealer, they should help you select the correct prop; which would usually be the next step higher in pitch to start.

Thanks! I have a feeling that is whats happening. I hope to have my mechanic check my rpms on a water test against my tach to make sure its correct. I will also get a 23p prop and check it again to make sure I am withing WOT.

 

[bluewaterboater]

Re: Factory prop sizing question

Update: I bought a 14 x 23p aluminum prop last night, put it on and took it for a test ride. It was a little choppy out so I couldn't put the boat through too many high speed paces BUT, it worked great!! I was able to go pretty much full out and it did not hit the rev limiter like you had advised. The boat ran great and of course because of the 23p I was able to get some pretty nice speed too!

Thanks for all your help!