Lack or thrust and low top speed

[K-9bot]

I bought an old AR230 and took it out for a test run. Both engines started up just fine (in the water) so we started out to the bay. My first observation was that the boat felt like the engines would rev up but the boat wasn't moving as fast as it should. I decided to open up the throttle all the way, the RPM’s reached the redline but the top speed was 42 MPH.

Took the boat back home and started to read and learn about this type of boat and realized that it is a direct drive system, therefore no reverse gear to worry about. I decided to replace the impellers (thanks SBT) since it could be the problem and if not it will improve performance in the end. After installing the impellers it appears that the problem got worse, now the boat was not able to reach even 20 MPH and one of the engine’s oil light was on.

To further investigate I decided to pull one engine out to have a closer look at everything from fuel line to impeller, looking for something like a “slipping clutch” which is what it felt like on the water. The only place that I could foresee such a failure is the Reduction Gear / Oil Pump / Crankcase.
It looks like the bearings in the crankcase have worn out allowing some play between the gears. This would allow the engine to run fast without moving the boat fast, and account for the low oil pressure since the oil pump is driven from the same place…
When I run the boat on the trailer out of the water, there is a metallic clinking sound and it is not from the impellers.

Question 1: Can this be the problem?
Question 2: Does anyone know where I can have the bearings replaced near Englewood FL?

 

[Babin Farms]

42mph is probably about right for that boat depending on a few things. Did you check to see if there was any sealant missing from around the intake grates or intake tunnel area? That will cause a loss in speed and cavitation. A dirty hull will reduce the speed (may not look dirty but feels rough).
The metal clinking sound is usually normal when running these boat out of the water on a hose.

 

[Cobra Jet Steering LLC]

Clinging and rattling on the trailer is normal unless you use the nylon pump liners, dissimilar metal corrosion causes the liners to get high spots and make contact with the impeller. pump spinning and the boat not going fast is cavitation it is usually something in the pump or bad sealant around the pump intake or leaking clean out plugs allowing air in or a lot of play between the impeller and the pump liner. these don't have clutches the only thing they have is splines on the drive shaft that go in the back of the intermediate bearing and then a vibration dampener between the power takeoff assembly and the intermediate bearing .

 

[K-9bot]

42mph is probably about right for that boat depending on a few things. Did you check to see if there was any sealant missing from around the intake grates or intake tunnel area? That will cause a loss in speed and cavitation. A dirty hull will reduce the speed (may not look dirty but feels rough).
The metal clinking sound is usually normal when running these boat out of the water on a hose.

Thanks for the replies and advice.. you guys got me thinking in a new direction.
I had a look at the intake and as you can see in the photos of each side, not only is sealant missing but one of the bars are bent. Clearly it need to be resealed but will the bent intake bar cause a problem?
Any additional advice is welcome, thanks!

 

[Cobra Jet Steering LLC]

Possibly but I don't know for sure , The sealant may be an issue the bent bar can probably be carefully reshaped. I know for decades I always modify my intake grates to keep most of the weeds out since the P W C's are horrible about weeds and I have never had a loss of top speed from doing it so I doubt this minor bend would be of any consequence. So swap them around and see if the issue follows the bent grate if you don't feel comfortable straightening the bar that would be one way to see if it has any effect

 

[Cobra Jet Steering LLC]

Looking at the intake grate I believe the bend may have been caused by a branch or a piece of wood that was forced into it and up into the impeller if that happened you may not see any obvious damage to the impeller but one of the blades may be distorted from an impact with a piece of wood . I would check that impeller very closely for any bend in the edge of one or more of the blades. I just can not see how an object went into that intake grate without contacting the impeller.

 

[zipper]

Which impellors did they sell you? If you lost 22 mph with an impellor swap, I would start there for slipping, cavitation. What does the tunnel look like? 42mph is not bad for that era. My 07 with more HP topped out at 48.8 gps with just me and 45 with 3 on board.

 

[Cobra Jet Steering LLC]

Sorry I missed the part about the new impellors, funny I stay with the factory impellers because every time I changed them to some other type I lost top end. Your description of the clutch slipping feeling is CAVITATION,, now one other issue with these boats is the clean out plugs gaskets going bad so get the rebuild kit and replace those gaskets and see if that helps.