Is this motor big enough

[rpatton]

looking at a 2000 pontoon boat 20' long that has a Johnson 70 hp motor on the back. Is this a decent combination or will this be under powered?

 

[steelespike]

A healthy 70 should do fine for most boating. Max speed could vary from about 19 mph to about 23 mph.
A family of 4 should be fine. probably could manage water sports. If not too heavily loaded.
You may want look fir the rating label.
As far as speed goes If a 70 makes 23 mph a 90 might make 27-30.
A 70 will use over 7 gallons per hour at wot.(wide open throttle)A 90 over 9 gph. A 70 will be screaming its guts out to
make its top speed, the 90 would be loafing at the 70s wot speed.

 

[rpatton]

Thanks

 

[Scott Danforth]

depends on what your intended use is for the party barge. just tooling along at idle, you could move it fine with a 30hp. Water sports may be an issue.

Spent a week this summer on a 22' barge with a 70 'rude on it and it would move along nicely with 14 people on board headed to a swimming hole or restaurant, or 3 people and a bunch of fishing gear

 

[Ike-110722]

Keep in mind the weight of the engine. A 90 HP outboard weighs over 100 lb more a 70. That does not include the additional gas you need for the 90. That's 100 lb pounds less of gear or people you can carry

 

[steelespike]

Actually the NADA book indicates the E. 2000 70hp 4 cylinder 4 stroke is about the same weight(320) as the Evinrude Etec.75 and 90 the 20" is 320,the 25" is 335.
If we are talking Yamaha there is a 106 lb increase with the 70 to 90.I think the older Evinrude 70 from the 80s/90s is about 270lb. 3 cylinder 2 stroke

 

[rpatton]

I am talking about a 70 2 stroke motor. I am told its a 2000 year.

 

[Scott Danforth]

ignoring the weight factor. what exactly are you wanting to do with the pontoon. for everything except pulling skiers and winning races the 70hp will be fine.

If you want to go fast, then a pontoon isnt the boat to start with.

 

[rpatton]

thanks Scott, I am looking to basically run a couple of miles to either fish,crab or sit on a sand bar with the wife and family and just kick back. I don't need to go fast but I don't want to take all day getting somewhere. I continually see toons running up the bay that cant get out of there own way, and that what I don't want. everybody say a 70 2 stroke will push me right along.

 

[aspeck]

70 is fine for most applications

 

[Scott Danforth]

thanks Scott, I am looking to basically run a couple of miles to either fish,crab or sit on a sand bar with the wife and family and just kick back. I don't need to go fast but I don't want to take all day getting somewhere. I continually see toons running up the bay that cant get out of there own way, and that what I don't want. everybody say a 70 2 stroke will push me right along.

If a 70hp will push a 22' pontoon in the mid 20's, it will push your 20' a bit faster. My friends 18' pontoon with a 30hp will move along at just shy of 18mph. However most pontoons you see tooling along that cant get out of their own way are because the guy/gal operating the throttle lever doesnt have it past idle.

 

[mla2ofus]

Just remember all that aluminum and salt water don't play well together. Better give 'er a good fresh water bath at home especially the carpeted bunks if that's what the tlr has.

Mike

 

[Lager]

This is what you need.
https://www.youtube.com/watch?v=DLRwkrBZzsA