bcarpman

I'm going out there tomorrow. I'll make it slip on purpose and try coming off plane to idle. I'm almost positive I did this two weeks ago, but maybe I never came to complete idle.

Griff

You need to try a Bravo 1 prop. Start with a 24 pitch.

Tabs way down will will keep the bow down, but will lift the stern and thus make the prop blow out easier.

The 4 blade you tried is to small of diameter and is a stern lifting prop.

MOBILEMERCMAN

Well, if you go with the prop slipping theory, Have you installed anything on the hull like a water pick up, any type of thru hull fitting, or transducer? As far as the clutch engagement theory goes if thats it, it will certainly give up for good soon. I hope you find problem soon.
Jim

throttleup

If your props are an older style with the rubber bushings you very well could have a spun hub. You refer to your 3B props as Bravos but I am assuming that you are referring to the drive style. Are your 23P and 25P 3B props Quicksilvers or Mirage propeller models? If so they have rubber bushings and you should have them checked out.

Julie

bcarpman

Sorry, the ones that I refered to as "Bravo" are Mirage's. Could a rubber bushing go then hook up again once it cools off? The latest one I just bought off a member and it's in great shape. He had it reworked if I remember correctly and I have a hard time believing it (and 4 other props) all have bad bushings.

I think what the other posts are refering to is the prop actually ventilating or whatever, and losing traction in the water. I'm having a hard time seeing how a 23p Mirage and 25p Mirage could both be ventilating that badly with such a deep x-dim and half throttle. My application seems like exactly what those props are designed for.

SB referered to a 3B he had that would lose bite and then never recover till he came off plane. How does that work?

Thanks Julie

SB

iTrader: (1)

I can't begin to tell you how bad / horrible it was.

I'd go simplistic at first trying to diagnose youre issue. Put last years prop on and take the drive shower off. Just to try of course. Everything will be same (other than motor) when it drove correctly.

If it now works, figure out if drive shower (supposedly this happens to some people) or prop.

If it doesn't work, have a solid hub prop handy. If that doesn't work, well......it's outdrive or coupler.

Can't imagine why either of these would act this way but many of us run into strange things that don't make much sense a little too often.

bcarpman

I went out and pulled the boat out of the water, checked the cable housing as recommended. Seemed ok. No fraying.

Then figured just for the heck of it, I'd try to band aid the issue (assuming the issue was shift cable related) by increasing the pull on the shift cable by moving it up in the slot. When I measured where it was, it was at about 2.5 inches from the fulcrum (at the bottom of the slot). The manual says it should be around 3 inches. Went to adjust it to 3 inches and it appears it was only barely tight. I think it must have been gradually slipping down towards the fulcrum over time.

Put it back to 3 inches and couldn't get any slip, even at WOT. Didn't have a full boat load of people, but I got into it with tabs down, tabs up, drive down, drive up, and couldn't get it to slip the way it had before.

I'm guessing that with all the sliping it's done to this point, the cone clutch is probably trash. On Monday I went ahead and ordered up a rebuilt drive anyway. I'll put it on and rebuild this one as a spare.

Figuring at mid way through the summer I'm not going to have any luck finding someone to change drives in a timmely manner. How difficult will it be to change myself? Anything I should watch out for? Any threads with specific instructions?

Thanks for everyone's help!

SB

iTrader: (1)

Glad you found it and thanks for sharing your info. Yet another pesky problem poss. solution to put in our old grey matter.

Wild Card 09

Sorry, but this doesn´t add up, for me. The throw issue on the cable sounds like you´ve found something, but I wasn´t aware that you can get a bravo to slip like that.

You mentioned in one of your posts that the 4 blade was a 13 3/4".

With 540 hp (or even 150 hp less) on a 4500+ lb 25 foot boat, you should be running 15 - 15 1/4" diameter props.

A smaller diameter pushing this size of boat will slip.

Griff

A Bravo drive won't slip like you are describing. It does not act like an automatic trans slipping on a car. It acts like a manual transmission. It is either in gear or its not. There is no in between.