Motor question

[broadway]

Ok guys I have a early 70's Johnson 15hp on a 1436 tracker topper my question is if I got a new motor with less hp would it be as fast?

 

[billyjoebigdaddy]

How many hp does the new one have? What pitch of prop was on the old one and also on the new one? How much weight is in your boat?

 

[broadway]

The old one has a 8x10 I think. I'd say about 300lbs. And I haven't picked a new one out yet. Just trying to get some help before I spend the money.

 

[JMichael]

If the next size down is a 9.9, I'd guess the answer to be No. The new motors are more powerful than older because the new motors ratings are at the prop rather than the drive shaft, but I don't think there is 5 hp worth of difference.

 

[Pappy]

Except for the 1974-76 engines the 9.9-15hp engines were pretty stout even before the rating changed from powerhead to propshaft.

JMichael nailed it pretty good considering your question was extremely vague at best.