Repowered 5.2 KC with twin 60 suzuki's.

[dan12345]

Tried the 15's with the motors at the same height. Not real successful at all. I was loaded up with 4 guys, gear, fuel and ice. It took forever to get up to 26 kts which was all it had, and it only reved to 5600. fuel economy was real average at 1.3 km per liter combined. Sure hope lifting the motors 20mm is going to make a lot of difference.

Cheers Chris.

4 guys fuel ice an gear is a fair bit of weight tho mate,what do the fellas running yamahas get with that sort of load? just curious as i havent loaded my rig up with that much weight yet either.

[Dean1]

Tried the 15's with the motors at the same height. Not real successful at all. I was loaded up with 4 guys, gear, fuel and ice. It took forever to get up to 26 kts which was all it had, and it only reved to 5600. fuel economy was real average at 1.3 km per liter combined. Sure hope lifting the motors 20mm is going to make a lot of difference.

Cheers Chris.

I was getting 1.3 klm per litre combined it is what all 5.2's seem to get with 60's 70's 90's 4 strokes. You will gain prob about another 2-3 kts and 300 rpm by lifting it another hole.

Fully loaded that is pretty good with the 60's as thats about what i was getting (loaded that is)
Best i ever got was 30kts with no load on my own so your getting close, it will never be a speed demon sorry to say but it seems the sukes have a bit more top end than the yammys.

Did you put spray plates on??

[Chris20984]

No haven't bothered with the spray plates, the only time the motors get any spray is when i come down off the plane as the arse of the boat is sinking down.

I knew it was not going to be super fast, but the responsiveness of the throttle was pretty disappointing, it just takes a long time to get moving and is pretty average in a bar crossing.

Will lift the motors 20 mm and go for a run with the 15's fully loaded and decide if i have to go back down to the 14's. It will be interesting to see the difference in speed verse fuel consumption.

[Chris20984]

Hey everybody, Good news, i finally got time to do some work to the boat.

Trip 1.

Lifted the motors up as high as they could go with the existing holes which puts the cav plate at 55 mm above the bottom of the hull. went for a run, could see 70 % of the cav plate. throws a big roster tail when trimmed up 3/4 or more. Had the 14x11 3/8 props on, two blokes, gear and full petrol. Super responsive on the throttle, up to cruise speed in seconds and hit the rev limiter pretty quick at 28 kts. getting 1.35 km/ltr

Trip 2.

Kept the motors at the same height, put the 15 x 11 1/4 props on, three blokes gear, full petrol. flat out the motors Didn't hit the rev limiter, about 300 revs under, only got to 28 kts. comfy cruise on 22 kts. much less responsive but still OK. fuel burn much the same.

Trip 3.

Got the drill out and drilled another set of holes in each pod higher than the originals, lifted the motors up to 70 mm above the bottom of the hull. Kept the 15 inch props on and went for a run with three blokes, full petrol and gear. could easily see 99 % of the cav plate on top of the water, cruise on 22 kts, hit rev limiter at 30 kts.

Thanks to everyone that helped me. I will post some pics soon, Cheers Chris.

[Salad Fingers]

no cavitation with the motors that high?

[Chris20984]

I can run in 2-3 ft chop any angle no problem at all. If i do a hard turn without adjusting the trim first so that the cat wont lean out it will get cavitation. They take a bit to learn to drive but it is well worth it.