Repowering an SR4

[Richardnhunt]

I’m looking to repower our SR4.

It’s used primarily on the Thames for coaching and training young people. It will get limited coastal use and it’s not designed to be operating on the edge - most of its like will be at slow speeds with some acceleration. So - experience please. I want a 4 stroke with power trim tilt - but stuck between 25hp & 30hp. Anyone have any experience of either size engine who can give a guide?

Cheers, Rich

[craig_c]

Had a 25hp 4 stroke Yamaha on a stripped bare SR4 some years ago with PTT.

Relatively quick with one person and trimmed to the max, not too bad with two light people but anything more is a struggle.

I would say a 40hp is more suitable for your use. Unless its an inland lake, you will miss the power

[Searider]

I've had two SR4Ms.
The first was a 1970s back to back seating version with a 50hp Yamaha 2 stroke. Was an absolute blast and did 37 knots.

The more recent one was a 1990s rescue version with the 2 seat jockey console. We had a 30hp Yamaha 2 stroke with power trim and tilt and it was a far better boat. Made about 28 knots and the power trim really made a difference.

For coaching duties with the odd blast on the sea a 30hp PTT 4 stroke will be perfect. Look at the weight - lighter is better!

[gjepson]

I've used several sr4's with 4 stroke 25, 30, 40 and 2 stroke 50's

The 30 will be well worth the extra money, especially if your likely to tow or have more than a couple of people on board.

A 40 is where I'd put my money a 50 is unnecessary

G