75 hp etec on alumacraft 165 navigator ?

[thejanster]

Ok guys have a 2006 75 etec on a 16.5 aluminum hull alumacraft . My problem is boat only runs 32 mph top speed with only 4200 rpms trimmed up with only 2 people.. Engine has about 100 hours and been like this from the start. Prop is a factory brp aluminum 17 pitch. Alumacraft has boat weighing 950lbs om their website.do I need to pitch down? unit is a tiller

 

[angus63]

Re: 75 hp etec on alumacraft 165 navigator ?

Welcome!!!!!
Are you certain the throttle is wide open? Check that the advance is fully advanced to the stop and throttle plates in the carbs are horizontal. Not sure what recommended WOT rpms is for that model, but 4200 is way low to me. Is the cavitation plate above the prop even with or slightly above the bottom of the hull? If you are still under warranty and you bought the boat/motor packaged, I'd find out the proper WOT rpm and ask them to setup for the high end of the range.
Good luck

 

[thejanster]

Re: 75 hp etec on alumacraft 165 navigator ?

4500-5500 is optimum they say. it is fuel injected so no carbs and cav plate is slightly higher than bottom of hul;l

 

[angus63]

Re: 75 hp etec on alumacraft 165 navigator ?

Sorry, not familiar with the etecs!!!!
What about cav plate and warranty?

 

[Monkaroo]

Re: 75 hp etec on alumacraft 165 navigator ?

This link might help you out .



http://www.marinedepo.com/proschool101.html

 

[seahorse5]

Re: 75 hp etec on alumacraft 165 navigator ?

See your dealer and ask him to print out the factory performance bulletin PE501 dated 5-02-07. He can get it online from his Dealerport site.

The Alumicraft Navigator 165 CS tested with a 75 E-TEC with a 17" Stainless Steel prop turned 5400 rpm just under 40mph and gave 4.8 miles per gallon. this was with 440# of people and gear along with a full gas tank, 22 gallons.

At 3500 rpm, 23.5 mph, the fuel burn was an incredible 6.3 miles per gallon.

If you boat and motor is not performing close to these numbers, then the setup is wrong, the motor is not putting out full power, or the boat hull has a hook or other flaw in it preventing good performance. Your dealer should be able to check things out for you.

 

[prose]

Re: 75 hp etec on alumacraft 165 navigator ?

I've got a Campion 485 Allante bowrider/play boat that weighs a stated 960lbs, so the 2 boats are close in weight...........I have a 2007 90hp E-Tec on which puts the weight up to approx. 1280 lbs...........I have tested 3 props thus far, all aluminum..........the one that came on the boat was a brp 17" pitch........I can obtain 5200 rpm's & 45-46 mph on the speedo, the second I have tried was a brp 15" pitch,obtained 5400-5500 rpm's & 42 mph on speedo, the third was a Hustler prop 17" pitch & can get 46-48 mph @ 5000 rpm..............So basically we have similar weight, & I'm using a 17" pitch max. with a 90hp, I'd try a 15" pitch prop & see the difference..............cheers..........

 

[steelespike]

Re: 75 hp etec on alumacraft 165 navigator ?

I just checked the BRP site unless there is some prob with my computer the titles are mixed up boats are all there they just don't match the click tab.
As you had the starcraft info I checked similar boats all came in around
40 mph with lowest rpm around 5250.A 970lb Sylvan did 41.1 at 5,400.W a stainless 13 7/8 X 15 prop.

 

[Silvertip]

Re: 75 hp etec on alumacraft 165 navigator ?

If the engine is not reaching at least 5000 rpm it needs to be looked at -- especially with a 17P prop. I have that same boat with a 75 Merc twisting a 19P prop and it runs as indicated in the post above. You can also go to the Alumacraft web site and look at a performance test for this boat.

 

[thejanster]

Re: 75 hp etec on alumacraft 165 navigator ?

Well guys its under warranty and its been in twice and last time they did a software update and told me that should fix it but still the same. I think ill try a diffrent dealer and see what they say. I was wondering if my tach is out but still im only reaching 32 mph?