OutDrive, Prop, HP Questions

[Roman S]

Hi, Happy New Year,
Two Questions, bear with me. Will be removing the Alpha one outdrive so I canw ork on the engine. Is it advisable to perhaps stick a couple of rags in the open hole while the outdrive is out? It will be out for a couple of months. When I am finished with the 350 5.7 L engine work I will have 30 to 40 more horses. Will I need to get a bigger prop to handle the extra HP.
Thanks Roman

 

[Don S]

Re: OutDrive, Prop, HP Questions

Is it advisable to perhaps stick a couple of rags in the open hole while the outdrive is out?

It won't hurt to protect things

When I am finished with the 350 5.7 L engine work I will have 30 to 40 more horses. Will I need to get a bigger prop to handle the extra HP.

Possibly, run it and check your WOT (Wide Open Throttle) rpm, that is what determines which prop you need.

 

[TilliamWe]

Re: OutDrive, Prop, HP Questions

Search on here or at another boat products site for a "Stern Drive Cover" from Stor-It. It's a plastic cover, with a gasket and bracket that bolts on in place of the drive and can support the trim rams too. About $15 plus shipping. Looks better than a cardboard cut out or rags stuffed in it.

 

[wire2]

Re: OutDrive, Prop, HP Questions

What was your wot rpm before? If it was close to max already, additional hp will put you over. If well under, you'll be ok with present prop.

 

[Roman S]

Re: OutDrive, Prop, HP Questions

My WOT is perfect right now. The boat was propped as when it was first biult in 1987, a Regal. However, with a new engine and a 30 to 40 more horses pushing in the back, it might need a bigger prop. Might?

 

[HT32BSX115]

Re: OutDrive, Prop, HP Questions

Uh...Like Don suggested. Don't do anything with the prop until you run it.

40 HP is not much additional HP.

Here's a good place to do some ball park calculations.
http://www.go-fast.com/Prop_Slip_Calculator.htm


Regards,


Rick