Need to narrow down a problem? Any help?

[Fatboyfrank]

Hello, my good friend has a challlenger 1800 with the 210 mercruiser v6, the problem is..... At 50 mph it revs maxed out and seems like it dosnt have any pull. It dosnt cavitate off the line but seems to have trouble on top end, almost like the boat is under proped. Does anyone make aftermarket impellers for thiis boat??? Not sure if the wear ring is bad but just wanted to see if there were similar issues with someones elses challenger. It comes out of the hole fine, just seems to have lost top end pull. Any suggestions would be great.

 

[Dr Honda]

50 mph... that's all she has.

As far as a impeller... you can contact scat-trak, and have them repitch your impeller if you want a little more up top.

 

[WAJetboating]

50 mph... that's all she has.

Yep, gotta agree here. The boat is the smaller one (18 feet), but they also have the smaller 210 engine. 50 MPH is about it. (I get ~54 on my 20 foot with the 240 engine).

However, I'm troubled by "just seems to have lost top end pull". Can you be more specific about what you're feeling at WOT?

As far as a impeller... you can contact scat-trak, and have them repitch your impeller if you want a little more up top.

Impros also works on these impellers. They can refurb to factory specs or repitch for different performance. Generally, you'll give up bottom end to gain top, and vice versa.

I'd climb under with a flashlight and check the clearance between the impeller and wear ring. It should be tight. Factory max is 0.050 inch on either side (0.100 total) but I would take action long before that. My clearance, BEFORE I had Impros refurb my prop, was still under 0.040 total. After refurb it's now under 0.020 total (IIRC). The performance is unbelievable - neck-snapping acceleration out of the hole and a solid top end too.

Report back with what you find when you climb under the boat!