Speed of a 20 foot Pontoon boat with 70 horsepower Johnson 1983 model year?

[Big Bubba]

Hello all,
I have a question. My Pontoon boat is a 1991 Lowes for Johnson model 202 or 20 footer boat that has a 1983, 70 horsepower Johnson outboard with a 13.75 X 13 pitch 3 blade aluminum pontoon boat prop that pushes the boat at 21 MPH at 5500 rpms wide open throttle. Does this sound right to you guys and my speedometer is a pitot tube type if that helps out? Thanks again Bob

 

[steelespike]

Re: Speed of a 20 foot Pontoon boat with 70 horsepower Johnson 1983 model year?

I would say your just about right.A GPS would be more accurate but pontoons are so variable log size,weight etc.18-22 would be a prettty normal range.

 

[finish line 88]

Re: Speed of a 20 foot Pontoon boat with 70 horsepower Johnson 1983 model year?

I have the same motor and prop size on a 20 ft Skipper Craft (fiberglass). I would be happy at that speed. I run around 17 mph at 5200 rpm.

 

[Rancherlee]

Re: Speed of a 20 foot Pontoon boat with 70 horsepower Johnson 1983 model year?

Hello all,
I have a question. My Pontoon boat is a 1991 Lowes for Johnson model 202 or 20 footer boat that has a 1983, 70 horsepower Johnson outboard with a 13.75 X 13 pitch 3 blade aluminum pontoon boat prop that pushes the boat at 21 MPH at 5500 rpms wide open throttle. Does this sound right to you guys and my speedometer is a pitot tube type if that helps out? Thanks again Bob

Also remember that an 83' engine is still rated at the powerhead and not the prop. You are probibly around 60ish hp at the prop.

 

[1976SRV190]

Re: Speed of a 20 foot Pontoon boat with 70 horsepower Johnson 1983 model year?

I'd say that is about right. My GFs mom has an 18ft with a Johnson 50 on it and at wot it makes about 18mph....

 

[chrisg]

Re: Speed of a 20 foot Pontoon boat with 70 horsepower Johnson 1983 model year?

Sounds like this is correct, I just got a '87 24-footer with a 115Merc OB. it also got up to 20MPH, at 5500RPM. so sounds like this is the top end for toons.