Can I replace a SX-M1 with a SX-A outdrive, why/why not?

[Giantmcm]

Hi all,

I am new fairly new to the world of boating, and purchased a 2006 Fourwinns Horizon 200 bow rider. It came with a Volvo Penta Emissions V-8 and a SX-M1 out drive with a 1.60 ratio.

Where the rest of the boat is phenomenal, the outdrive has a lot of really deep pitting, scaling from a lack of anodes being replaced by the previous owners, and there is something inside the outdrive that sounds like a rhythmic knocking against the housing. I think it's the lower half of the housing, but not 100% positive.

Running the boat the last two days here were the symptoms:
Day 1: boat ran well, averaged about 3500k rpms at about 37mph all ran smoothly and boat ran great, for almost 2 hours solid.

Day 2: left our docking site and couldn't get past 25mph at 4k rpms. I shut it down right away and checked things over as best I knew how. Oil level was good in the motor. Fired it back up again and slowly sped up. Engine oil pressure was a little high as if the motor was being worked hard. And we limped back the 23 nautical miles at 3750 rpms and 23 mph, shutting down periodically to let the kids swim and the boat rest. Everytime I trimmed the motor to the top position, I could here the rhythmic clanking in the outboard, definitely something "slapping" the aluminum housing.

At this point, my plan is to either replace the outdrive and transom, or remove it all from the boat, tear it apart, and see if I can bead blast it all down, repaint, and rebuild the assembly if it seems salvagable.

Can I use any SX-M outdrive and do the ratios really make that much of a difference?

I also want to understand how ratios change the performance of the boat? I hope to install a 4 blade on my boat to get me out of the hole better as it is used for towing tunes, causing, and possible skiing and wakeboarding in the future.

And any other suggestions as to what I can replace my SX-M1 outdrive with is also encouraged. I know there was the sx-cobra series, and a dual prop series, just wanting to learn more to better understand what I am up against.

Thanks,

John

 

[Bondo]

Everytime I trimmed the motor to the top position, I could here the rhythmic clanking in the outboard, definitely something "slapping" the aluminum housing.

and do the ratios really make that much of a difference?

Ayuh,..... Welcome Aboard,..... When you raise the drive into the Tilt zone, yer stressin' the u-joints, causin' that noise,....
Don't do that,.... raise it only in the Trim zone,....

'n yes, the ratio is extremely important for driveability,...
A taller ratio, 'n that 3.0l will be a pig, lugging the motor,....

 

[dubs283]

Ratio in the drive does matter, along with propping, hull design/size, etc...

That said, pretty sure you will be able to mate any sx-m drive to your bell housing. Caveat is actual model designation, ratio, prop, etc...

You should investigate engine running poorly as more engine related, not focused on running gear. If you're running in salt, all bets with a Volvo are off. They suffer major corrosion in fresh water, so.....

 

[Giantmcm]

Ayuh,..... Welcome Aboard,..... When you raise the drive into the Tilt zone, yer stressin' the u-joints, causin' that noise,....
Don't do that,.... raise it only in the Trim zone,....

'n yes, the ratio is extremely important for driveability,...
A taller ratio, 'n that 3.0l will be a pig, lugging the motor,....

Thanks for the reply and the welcoming, I take it the tilt zone is a high point in the trim, and the trim zone is the bottom 3/4 of the trim levels, is that about right?

And I am running the 5.0l GL motor by volvo...what ratios would be wise/ok to run with my motor in a 2006 Fourwinns Horizon 200?

 

[Giantmcm]

Ratio in the drive does matter, along with propping, hull design/size, etc...

That said, pretty sure you will be able to mate any sx-m drive to your bell housing. Caveat is actual model designation, ratio, prop, etc...

You should investigate engine running poorly as more engine related, not focused on running gear. If you're running in salt, all bets with a Volvo are off. They suffer major corrosion in fresh water, so.....

Thanks Dubs for the thoughts/info.

I looked into the motor, and it is running like a top, flawlessly. The outdrive is honestly where my concerns are at, I feel like the issue lies there.

It is a freshwater boat only, and there is a lot of calcium built up and the paint is flaking like dandruff on a bad hair day. It's pretty bad.