Problems With Merc X Drives Donzi 35zr

[unruly crew]

We have just purchased a Donzi 35ZR with twin 496HOs and have broken an upper gear in both X drives. Anyone else out there having the same problem. We are looking into upgrading to XR drives.

[harbormaster]

Thats really odd. You must be driving the crap out of it.

(remember! throttle back when the boat leaves the water. Also never slam your throttles forward.) These 2 things can lead to premature outdrive failure.

Do you have drive showers? If not you need to add them. The decreased heat can lengthen the life of your drives

An XR will give you a tad more strength BUT be prepared to lose about 4 mph top in. This is due to the straight cut gears.

What you might consider is reduce the gearing from a 1.50 to 1.36 and put a smaller pitch prop on it. It will decrease the stress on your drive gears.

Just my 2 cents - (anything I say could be totally wrong.)

[Shanghied Again]

Good Morning: we were the boat you were tied next to at the 1000 Islands Poker Run. The 496s with the X drives on the East Coast are holding up very well on the 35ZRs most boats in this reagion run in the back bays and Ocean, The only Issue I have seen with an X Drive is with my boat way back when and it was a warranty defect I lost the top gear she cracked she has been replaced and I have been running the boat with no Issues for 2 years. You have to watch getting a lot of air and over trimming but changing to XR drives will help but no drive likes to be over trimmed and or get air. When you launch make sure you back off the throttles till you hit solid water, Don't think when you land back in that you are in solid water yet thats when damage can occure, when you first land back in the water and you give it the throttle again there is still a lot of air under the boat that would cause prop blow out and the torque gets so great on a drive that she will start to put pressure on the clutches and gears. also when you first get the boat on plane make sure she is on plane first before you start to trim up. The 35 ZR best speed is at 5 some guys try to trim up to 7 to get top end, you may get another mile an hour out of the boat but you now start getting more slip especilly when you hit waves. The 496 with the X drives are pretty dependable and are used on a lot of applications. The 35 ZR is designed for speed and were you boat should run 78-80 mph once you hit top speed don't try to get more out of her you are only going to hurt something. Hopefully you have a Merc Warranty. But going with XR drives can be an expensive investment and no horse power gains.

[mrfixxall]

If your currently running a 4 blade propeller you may wany to consider switching to a 3 blade prop,a 3 blade prop dont bite the water so hard and are more forgiving....like harbormaster said going to a 1.36 ratio is a stronger gear may be a better drive for your boat....

[harbormaster]

Oh Yeah one last thing.

Going down one gear from a 1.5 to a 1.36 you would lower the prop's pitch size by 4.

Example: If you started out with a 1.5 ratio drive and 28 pitch prop, If you go to a 1.36 ratio drive you would use a 24 pitch prop.

[Mr X]

Oh Yeah one last thing.
Going down one gear from a 1.5 to a 1.36 you would lower the prop's pitch size by 4.
Example: If you started out with a 1.5 ratio drive and 28 pitch prop, If you go to a 1.36 ratio drive you would use a 24 pitch prop.

This will also radically change the way the boat handles, and its usually not better.
Bow steering, chine walking etc.