2013 75HP optimax problem

kxracedad

Cadet
Joined
Jul 3, 2010
Messages
10
Boat is a brand new Bass Tracker with 75HP OptiMax, its going to go back to the dealer for warranty repair but I am curious if anyone knows what is going on (to avoid the inevitable run around from the dealer)

Cruising down the lake between 5300 and 5400 rpm at 44 mph, motor trimmed out. For no reason at all, hand not even on throttle the rpms will jump to 6k and speed will go down to about 37. Has happened several times and when it does the motor sounds horrible. Almost seems like a clutch slipping in a car. The motor recovers, I trim the motor back down and then have to go back up to get it back up to speed.

Also, seems to me like there is too much vibration at idle speed in no wake. that could be my imagination but it vibrates the whole boat.

any ideas?
 

Fleetwin

Lieutenant Junior Grade
Joined
Nov 23, 2011
Messages
1,141
Re: 2013 75HP optimax problem

(to avoid the inevitable run around from the dealer)

Please don't go in with that attitude or that's exactly what you'll get.

Cruising down the lake between 5300 and 5400 rpm at 44 mph, motor trimmed out. For no reason at all, hand not even on throttle the rpms will jump to 6k and speed will go down to about 37. Has happened several times and when it does the motor sounds horrible. Almost seems like a clutch slipping in a car. The motor recovers, I trim the motor back down and then have to go back up to get it back up to speed.

It could be a slipping prop hub but that would be rare on a new engine/prop. Possible though.
Also, seems to me like there is too much vibration at idle speed in no wake. that could be my imagination but it vibrates the whole boat.

any ideas?

They should be able to do a lot of the diagnostics, electronically. That should give them a pretty good idea if the engine is healthy and has shown any misfiring, etc.

Good luck. Give them the best description possible of what is going on.
 

kxracedad

Cadet
Joined
Jul 3, 2010
Messages
10
Re: 2013 75HP optimax problem

I wont go in with that attitude, but I have gotten BS from this dealer before. What I dont want is for them to come up with some line of crap and wind up having to take it back to them several times to get it fixed. I generally go with the attitude of keeping my mouth shut until I think I'm being fed a line of BS and then say something if I am 100% sure I am on solid ground. That being said, I agree....going in with that attitude is sure to get unfavorable results.

would a slipping prop hub cause the vibration I am talking about?

if thats what it is, then it is what it is....everyone makes junk once in a while, but I will expect them to stand behind it.

all in all I am very happy with this boat, its actually my dads. Tracker did a fine job when they designed it
 

Fun Times

Moderator
Staff member
Joined
May 16, 2009
Messages
9,265
Re: 2013 75HP optimax problem

You may also be experiencing propeller cavitation.

It could be a number of things that could cause propeller cavitation like, over trimming the engine, engine height set up to high, something mounted on the boats hull in the water flow path to the propeller causing air pockets around the propeller area.

Hope you get it figured out, Good luck.:)
 

kxracedad

Cadet
Joined
Jul 3, 2010
Messages
10
Re: 2013 75HP optimax problem

It's not cavitation, boat has been in the shop, out of the shop and is now back in

they originally set the motor where tracker recommends, first time in the shop they decided the motor needed to go down. tested it, and it didnt do it. Dad took it fishing this past weekend and it did it again. Now they are saying the prop isnt holding water and so they are going to try to adding a wedge or changing props or both

As for the slipping prop hub, the way the optimax is setup it doesnt have a prop hub to slip....it either engages and stays engaged or it doesnt engage at all.....at least that is what the dealer said
 
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