Ventilation problem

[havensduane]

I have an 18’ pontoon with an 2000 Johnson 50 hp. I recently changed the prop with a new aftermarket because the old prop had two bent fins. Ever since I’ve been having ventilation problems. I purchased a hydra-foil and installed it to no avail. The motor is mounted all the way down. Am I looking at purchasing another prop? Thanks in advance.

 

[Sea Rider]

Welcome to IBoats,

Ventilates on flat calm, choppy water conditions, at sharp turns at speed ? Was the toon running with deck load evenly distributed ? How did you set the trim angle ?

Happy Boating​

 

[havensduane]

Welcome to IBoats,

Ventilates on flat calm, choppy water conditions, at sharp turns at speed ? Was the toon running with deck load evenly distributed ? How did you set the trim angle ?

Happy Boating​

It ventilates mostly on choppy water, doesn’t seem to make any difference on weight distribution, have tried moving people around to equal out but didn’t help.

 

[jlh3rd]

I dont know johnson outboards, but I've become fairly involved and knowledgeable with propping my new merc. 115 hp, CT. . I learned a lot.
what prop ..diameter, pitch, and blades were you running that didn't have ventilation issues and what do you have now?
I learned my gearcase size determines what prop I can use and if it's wrong, the through-the-hub exhaust causes ventilation....some aftermarket props require a "spacer" between the prop and gearcase and if it's missing, you get ventilation....

Is there a chance that there is a mismatch or spacer missing?

 

[Scott Danforth]

Did you get the same prop, or a stern lifting prop?

 

[havensduane]

I dont know johnson outboards, but I've become fairly involved and knowledgeable with propping my new merc. 115 hp, CT. . I learned a lot.
what prop ..diameter, pitch, and blades were you running that didn't have ventilation issues and what do you have now?
I learned my gearcase size determines what prop I can use and if it's wrong, the through-the-hub exhaust causes ventilation....some aftermarket props require a "spacer" between the prop and gearcase and if it's missing, you get ventilation....

Is there a chance that there is a mismatch or spacer missing?

I went back with the same size as was on it which I’m assuming was factory. I will do some research on the rest. Thanks.

 

[havensduane]

Did you get the same prop, or a stern lifting prop?

Same prop.

 

[Sea Rider]

Test this out : with deck load evenly distributed go for a wot run on flat calm no wind water conditions, with motor running trimmed to neutral and combo at plane have someone to pull his head side of motor to check and report at which of both lower leg's plates is the hardened water flow passing by. Is it passing around the lower AV plate, under the small upper plate or around middlle of both plates. The idea is to stay boating with the new prop after a fine motor/transom height tuning which probably the toon needs ?

Happy Boating​