18SF mounting height/prop for ETEC 150

[fishstu]

I am looking at moving my motor up - not sure the height of cav. plate is relative to the hull keel - boat is in slip right now.

The 150 Etec on my 20 SC with a SS 4B 14.5 x 15P BRP Cyclone limits out around 40 mph at 5000 / 5100 rpm which I think 5500/5750 would be the optimal top end.
Otherwise the boat runs great, tends to propose a bit until I trim motor and use trim tabs.

I will post more when I take measurements - the 18 SC is very similar to the 20 SC.

Your current height of 2 1/2 inches above the keel doesn't sound too high from what I have read- another prop may work better - or maybe lowering one hole might be the sweet spot.

The boat next to me just had a rebuilt transom and a stainless marine bracket fitted to replace his old bracket. His old prop did not work well at all, at first it looked like the engine was too high compared to the original height before the work - but the guy that did the work took a ride and said- nope the engine is at the right height need to change the prop. He changed the prop - completely different boat, problem solved.

His old transom and bracket were water logged with maybe 500 lbs of water which changed every thing. His situation got me thinking about mine