20' Riviera Cruiser Speed Question

[christopher425]

Hey Everyone! I've got a 1990 Riviera Cruiser 20 footer with an '87 Mariner 45hp 2-stroke powering it (that's what came when I purchased). It's got an 11.1x13 prop and at WOT using a GPS app on my phone I hit 14mph average with me and another buddy on the lake. I've got manual trim n it, so I do still need to probably experiment with what works best. Does this speed sound about right for my boat/motor combo? Im not expecting nor wanting anything lightning fast, just wanna make sure my rig is operating ok. Thanks for any help/advice offered!

 

[ahicks]

I think you're close. There may be a mile or 2 an hour hiding somewhere if you screw with it enough, but most people will find it's not worth it.....

 

[Scott Danforth]

What is your boat rated for? Make sure you have at least 75% of rating

 

[jlh3rd]

Isn't it the rpm range achieved for a specific motor, not the speed, that is important?....

 

[christopher425]

What is your boat rated for? Make sure you have at least 75% of rating

From what I've been able to research and find, it's rated for 70hp. So, that would be a little undersized at 45hp which is what I have, but I'm not looking to upgrade right now. As I mentioned, I know she's gonna putt along and not blaze the open waters lol.

 

[christopher425]

Isn't it the rpm range achieved for a specific motor, not the speed, that is important?....

Correct. I've got a tach ready to install and I'm planning to do that in the spring. Like my first post said, I'm just wanting to know if this speed sounds somewhat accurate for my setup. Still kinda new here and trying to gain as much knowledge as I can.

 

[ahicks]

From what I've been able to research and find, it's rated for 70hp. So, that would be a little undersized at 45hp which is what I have, but I'm not looking to upgrade right now. As I mentioned, I know she's gonna putt along and not blaze the open waters lol.

When talking pontoon boats, especially those used on inland lakes, IMHO, it's more run whatever you want to. There certainly nothing wrong with a 45 on a 20' boat. That's actually one of the more common setups you'll run across, even on 24' boats. As mentioned, you're fine....

I would mention though, that particular motor is not real well known for how quiet it runs. If that's an issue, about any other brand will be noticeably quieter. If you do get around to upgrading it, a 4 stroke 40-50 will make you think you died and went to heaven. Anyone I know that's tried one has been spoiled immediately..... A VERY popular upgrade for pontoon boat owners!

 

[christopher425]

When talking pontoon boats, especially those used on inland lakes, IMHO, it's more run whatever you want to. There certainly nothing wrong with a 45 on a 20' boat. That's actually one of the more common setups you'll run across, even on 24' boats. As mentioned, you're fine....

I would mention though, that particular motor is not real well known for how quiet it runs. If that's an issue, about any other brand will be noticeably quieter. If you do get around to upgrading it, a 4 stroke 40-50 will make you think you died and went to heaven. Anyone I know that's tried one has been spoiled immediately..... A VERY popular upgrade for pontoon boat owners!

Thanks for the pro-tip ahicks! I’ll definitely keep that in consideration for the future.

 

[christopher425]

I just wanted to post a follow-up to this thread b/c I know that step can sometimes be forgotten. Long story short, I need to replace my lower carb and I also put a lower pitched prop on (11.8x10) as the previous one I purchased was not actually what the manufacturer recommended.. The motor has never run better! No misses, surging, or loss of rpm. I actually gained 4 mph in speed and my rpm also went up to within the acceptable range as it should be. I really appreciate all the help from everyone on here and sometimes I suppose we just have to go step by step until we get our issue resolved. Slow down...think it through...and use your gut. That helped me out tons. Can't wait to get it out on the water in the spring. Happy & safe boating everyone!