Over Propped Johnson GT150 on a Stratos 270

[wdbcov]

I recently bought a 94 Stratos 270 17'9", with an older 1985 Johnson GT150 mounted on it. It seems to "bogg" when I try to get out of the hole. It came with a 14.5 X23 Raker prop. I think it may be over propped and may need a smaller diameter 4 blade, less pitch prop to get up out of the water quicker....

WOT is currently is reading ~4200 RPM.... boat is running ~50-55 mph. No major issues while running. I don't care about the speed, I want to stop the bogging and ride smoothly. You guys are the Xperts, I am just learning. What Size prop should I be running, should I try something, or should I buy another motor??????

 

[wyngo]

Re: Over Propped Johnson GT150 on a Stratos 270

I have an 89 285 xl and run a 13x23 4 blade. It is slow out of the hole, but I can reach upper 50's at 5400 - 5500 rpm. Your 4200 rpm seems low at that speed, and I would check the tach as it is probably running around 5200 rpm, and you want to be around 5500 -5800 rpm. Dropping a prop size will help getting out of the hole, but be careful as I believe for every size you frop down your rpm will increase by 200. example 14x23=4200, a 14x21 would equal 4400 and so on.

 

[wdbcov]

Re: Over Propped Johnson GT150 on a Stratos 270

Thanks for the info, I will investigate the RPM gauge this weekend. so do you think 14.5x23 prop(cupped) is too much or should I just learn to cope with the slow hole shot, and schedule a session with a local Psychologist ..... I cannot stand the boggish hole shot, but I can always sale this heavy boat and improve that.

 

[wyngo]

Re: Over Propped Johnson GT150 on a Stratos 270

If you like the boat, just look into a new (used) prop. I also have a 13x18 4 blade that makes the boat jump out of the hole, but no top end. Your other option is to talk to a prop shop in which they can recommend a prop or modify the one you have. They may even let you try a couple of props to see which one you like the best before you purchase one. Many ways to solve this issue.

 

[wdbcov]

Re: Over Propped Johnson GT150 on a Stratos 270

10-4 wyngo, i will definitely look into, an d reply back. plan on checking out the rpm first...

 

[wdbcov]

Re: Over Propped Johnson GT150 on a Stratos 270

RPM gauge is not reading properly... will replace soon.