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Thread: Wooldridge Alaskan and Cavitation problem

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    Default Wooldridge Alaskan and Cavitation problem

    I have a new to me 2002 Alaskan with a 150/105 yamaha vmax 2 stroke jet. I took it out for the first time and ran it on a local river and lake with calm water. When ever I tried to turn with on step the boat would slide and cavitate losing ALL power. I was not doing a sharp turn either. Only way I could turn while on step was to make slow wide sweeping turns. The hull does have some dings and dents, but nothing major. Any idea on why handling is so bad on step? Everything I have researched before said the Alaskan was a great handling OB jet boat.

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    Moderator stid2677's Avatar
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    I have a 2005 and it is an awesome sled. I would call or email Wooldridge and ask them, they are great at taking care of their boats even older ones.

    My guess would be that the engine is not low enough or the jet may have some damage.

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    The first thing I would check is the height of the jet foot in relation to the bottom of the transom and the hull forward of the transom. The pin that holds the rocks guards into the forward portion of the foot should be at the same height as the bottom of the transom. Any decent dents in the hull, ahead of the foot, will direct water down and away from the foot. Also, you made need a slight mod to the foot, adding "wings on each side to help direct water into the foot on corners.

    Another thing may be the trim, as it is now it may be trimmed to high. As for sliding, thats what jets do, learn to use it to your advantage, throttle control is a major aspect of jet boating and makes a huge difference in "make or break" handling.

    If you can, post a picture of the stern form the side showing the foot to transom height, and the bottom of the hull just forward of the transom.

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    my alaskan does not cavitate unless i am in reverse. the motor needs to be the right height from the tunnel not the bottom of the boat and do you have a piece of plastic as a splash guard? i did my motor height a few times on a lake to get it how i wanted it and it does not slide in the corners.

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    Moderator bkmail's Avatar
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    I'll also ask;
    Is it a tunnel hull?
    Have you checked the tolerances between the impeller and wear sleeve?
    I think .338WM is probably right on with his train of thought.
    BK
    A few pics would be helpful...

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    Supporting Member Old John's Avatar
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    without being able to look to see how the jet foot and the bottom of the boat line up, I'd agree with Stidd and 338.
    Think the motor is setting too high it doesn't take much to be wrong in this case.

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    I have a 2006 with a 115 Suzuki. I have to 'try' to make it slip in a turn. Is there a piece of plastic between the bottom of the boat and the front of the jet unit? Is the hull damaged in the tunnel? Is your impeller shimmed right? Does it porpose when going straight line? Is your motor trimmed all the way down?

    Post a pic if you can.

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    Moderator LuJon's Avatar
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    The Alaskan should be a tunnel hull. Since it is "new 2 U" I would first check out the impeller set-up. It should not cavitate and it should not be skidding under normal cornering. The Wooldridge is unlike most other jet boats in that regard. I would go take some pics and post them up here so we can take a look at your setup. I would also call Glen or Grant at Wooldridge to chat with them.

    Some documents on the topic.
    http://www.outboardjets.com/catalog/...s%20Manual.pdf

    http://www.outboardjets.com/pdfs/IMPELLERSHARPENING.pdf


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    I will take a couple pics this evening and post them. It did porpoise some when cruising pretty fast. The foot fits snuggly right under the spray guard in the tunnel when trimmed down. Pics to come this evening.

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    Quote Originally Posted by john2 View Post
    I will take a couple pics this evening and post them. It did porpoise some when cruising pretty fast. The foot fits snuggly right under the spray guard in the tunnel when trimmed down. Pics to come this evening.
    My E-mail is glen@wooldridgeboats.com send me your phone number and the best time to call you. Glen

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    Thank you Glen! I look forward to talking to you. Here are some pictures.

    The last photo is of a chine that is dented pretty bad. It now does not extend below the bottom of the transom.





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    It looks to me like your trim tab equivalents at the back of the boat are way bent up. They make a big difference with the porpoising thing and how it tracks right to left. Also, how is it that your jet is that color. Did you paint it? I have the 17.5 also and would love to hear what Glen has to say about the cavitation thing as well as the porpoising. Bet you it is your impeller. Keep us posted.

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    Member Yukoner's Avatar
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    If nothing else, fix the wings on the intake foot, they should be bent at maybe 110-120 degrees with respect to the foot.
    Never wrestle with a pig.
    you both get dirty;
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    Wow, that thing looks like it fell half off the trailer and was dragged down the road.

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    From the wear and tear on the foot, I was bet that pump has ate a lot of gravel. Would be wise to check everything out. I bet the impeller has damage.
    "I refuse to let the things I can't do stop me from doing the things I can"
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    The impeller is pretty new. I was given a spare stainless impeller when I purchased the boat. The spare is the older one and it is sharpened nicely. I will look closer at the one in the unit. Lower unit is painted. I will try to bend the tabs down. I guess the best way would be to use a mallet and hammer them to the desired angle?

    I appreciate all of your suggestions!

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    Try bending them with a large vice grip type device. This you may want to ask Glen about. The hammer thing did not work well for me. It was very loud and I felt I was just going to pop welds. Also, the trim tabs are sensitive to change. A 1/2 inch below the planing surface can be a lot.

    I kept my impeller sharp and thought I was doing real good. I took it to the prop doc guy and he told me it was worn out and rebuilt it for me. Wow, what a difference. It also makes a big difference when it is shimmed correctly. Just being sharp may not be enough. Hope this helps.

    My 17.5 porpoised a bit at high speeds when it was not loaded. It has a heavy 4 stroke and a kicker on the back. I decided it was a weight and balance thing and put a bunch of my tools and emergency gear in the bow. No more problems. I am very conscious of weight and balance now. My boat does not like to be back heavy. It handles like a dream when I get it all right and I love the boat.

    Also, it looks like your boat has been "used" a bit. Is it possible the boat is bent or cupped? Again, Glen may have better insights.

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    Glen,

    It was a pleasure speaking with you! Your insight and knowledge is greatly appreciated. Hopefully, after some testing and tweaking my boat will be running great!

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    lujon,
    Re:the picture of the impellar being sharpened, the bevel on the impellar should be on the other side of the blade, you want the bevel to draw the water into the pump, if you bevel it this way it pushes it away. I saw the pdf from outboard jets and with all due respect it works better the other way, DD

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    Quote Originally Posted by Club220 View Post
    lujon,
    Re:the picture of the impellar being sharpened, the bevel on the impellar should be on the other side of the blade, you want the bevel to draw the water into the pump, if you bevel it this way it pushes it away. I saw the pdf from outboard jets and with all due respect it works better the other way, DD
    Not according to outboardjets.com. The photo shows it being done correctly.
    http://www.outboardjets.com/pdfs/IMPELLERSHARPENING.pdf

    The diagram shows the impeller as it would be installed. I went ahead and reoriented them so that they are the same

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