Wandering mariah!

[damie]

I have a 99 mariah 18ft bow rider with 4.3L, 19 pitch prop ally. alpha one drive, and have two problems.<br /><br />First is while trolling through marina she wanders port to starboard, if i increase my speed to above 7MPH it dissapears, also hole shot full throttle if i go straight all is O.K, However if i turn a little at the same time port or starboard i will loose grip and RPMs will go up until i throttle back.<br />this is on a smaller boat to the thread running at the moment.<br />Anyone have any ideas?<br />thanks.

 

[Don S]

Re: Wandering mariah!

First is while trolling through marina she wanders port to starboard, if i increase my speed to above 7MPH it dissapears, also hole shot full throttle if i go straight all is O.K

That's typical of single prop I/O's.<br /><br />

if i turn a little at the same time port or starboard i will loose grip and RPMs will go up until i throttle back.<br />this is on a smaller boat to the thread running at the moment.<br />

That is also normal. Try trimming the drive all the way down. It's actually safer to start off straight not turning and trying to get on plane at the same time.

 

[damie]

Re: Wandering mariah!

regarding the wandering...my old boat never did this nor does my mates boat of wich is the same as mine only with the 3.0l engine, the only difference that i can see is the trim tab above the prop..i just have a blanking plate and i have noticed that some other newer alphas dont have them either.<br />my mates does.<br /><br />do you think that i should increase pitch to 21 will this stop cavitation from prop or do you recommend doelfins?

 

[TilliamWe]

Re: Wandering mariah!

I don't think you need a doelphin. You need to make sure that your drive is trimmed all the way down, when you are taking off.<br />A higher pitch prop (of the same style) will not stop a ventilation problem.<br /><br />As far as the wander, it is normal. If there is room, you may want to get the sacrificial anode for the ventilation plate that sticks down. And then adust it's angle and see if that helps the slow speed wander. Just note, if your prop diameter is large, the prop might hit the anode, and that's BAD

 

[Don S]

Re: Wandering mariah!

Prop size is used to get the proper WOT rpm. If you have the right rpm now, going to a higher pitch prop would overload the engine and cause reduced engine life. Trimming the drive down and putting the trim tabs all the way down while at slow speed can help with the wander. Hull design has a lot to do with the wandering problem. So don't compare 2 different hull styles. Overcorrecting is also a problem. Make small corrections and give them time to take effect.

 

[mercrewser]

Re: Wandering mariah!

If you have a vented propeller (holes in the hub by the blades) it can be very sensitive to excessive ventilation during turns and certain trim at high loads (acceleration). BTW, I had a 1992 Mariah 2350ZC. Man I miss that boat. Got compliments all the time. Had it for 6 yrs but didnt know how much I loved it till it was gone.

 

[damie]

Re: Wandering mariah!

Thanks everyone for your advise when she goes back in the water i will experiment.<br />Kind regards from the U.K.