1987 22-2 Ospery re-power

[fitz73222]

Hey Bush,
What prop pitch are you running and what is your WOT RPM's? What is your engine spacing? Assuming a 12 degree deadrise for an Osprey it looks like the engines need to be raised as high as they can go. Are you running 20" or 25" shaft lenghts? The engines should be raised up. I think the issue here is the engines are way to low. Where are the anti- cavitaion plates relative to the bottom of the boat? I know for a fact that stock Yamaha aluminum props are not the best choice but that comes later after the engines are the right height. We need another 5-6 mph out of this boat and I think between engine height and props we can easily get there. You should be running in the upper 30's (MPH) with this rig.

[Capt Matt]

I agree the motors look to be mounted really low which causes lots of drag
You will get it worked out, as with any repower it will need some fine tuning
Capt Matt

[gran398]

Agree, the spray you are getting out of the hole is independent of the scuppers, it is most likely the cavitation plates digging.

Please take a pic of the cav plates with a straightedge underneath the plate and engaging the hull. As Fitz and Matt mention, just a bit of adjustment, good to go

[Bushleaguer]

Props are 13-1/2 x 15.  I'm turning right at 6K at WOT.  20" shafts.
Here's a couple of pics I took in the driveway.  No straight edge, but you can eyeball where the cav plate is pretty good:
 






Thanks for the great advice guys- I never would have thought of the motors being too low.  Just trusted the installer to know what they were doing.....

[seabob4]

Keep in mind, you want the cav plates to be within 1/2" +/- of the hull bottom, preferably 1/2" above.  Eye balling is good, but get a straight edge to make sure...

[Bushleaguer]

Can do. I'll pull her back out and get it measured up.  I have to experiment with moving the axles on the trailer anyway- the extra weight in the back has taken away almost all of my tongue weight.

Is it possible that since the extra weight has pushed the waterline in the stern down 2"+ that the cav plate should be higher than standard, or is the correct setting just in relation to the hull bottom?

[gran398]

Exactly as Bob said. You are on a slant vis-a-vis the transom with twins....so the outside of the plate will end up a little high, the inside a little low. Just make the center of the plate even to the hull bottom with a straightedge, you should be golden.

You should notice a big difference right away

[Bushleaguer]

Got it!  Even with my trick eye, I'm guessing by looking at those pics above, especially the view from about 45 degrees starboard, that they do look quite a bit low.  I'll have to look and see if this is something I can handle myself- I would think that I may have to re-seal everything with 5200.  I'll see what's involved.

[Bushleaguer]

Also, the anti-cav plate we are discussing would be the largest one, directly above the prop, correct?  There seems to be a "secondary one" for lack of a better term above that one.

[gran398]

Yes that is correct, the big plate.

To move the engines up, just pull the pins and lift/slide them up, then reinstall the pins. There are several holes for adjustment. I'd take them back to the dealer, tell them what you want, supervise if possible. That way down the road they can't claim "unauthorized mechanic" etc.

[Capt. Bob]

To move the engines up, just pull the pins and lift/slide them up, then reinstall the pins. There are several holes for adjustment.

By pins, you mean the transom bolts correct?

Unbolt and remove the bottoms and loosen the tops?

[gran398]

Not sure exactly how the F 70 is set up compared to my Mercs, so called the dealer.

You got it CB. Affix the engine to the stand, knock all four bolts back in towards the transom (no need to remove them, just knock them back close to the transom) jack up the engines where you want them, and reinstall via the new holes.

[Capt Matt]

Your probably going to need a lifting eye and come along or motor lift. Take it back to dealer they should do it as part of the repower
Capt Matt

[redemn93]

sooooo how about sealing them?  you need to pull the motors away from the transom, clean up the old sealer and reapply.  wait atleast 24 hours before hitting the water again.  

if the shop didnt mention sealer i really hole the used some.  or else you have a wet transom now.

[Bushleaguer]

They did use sealer- looks like black 4200 or 5200 to me.  I'll see if I can watch them do it and make sure that everything is bolted / sealed up tight.  I'm kinda disappointed that they didn't catch this during the initial install.  You would think they would know what the proper height adjustment was wouldn't you??