Will not plane out

[dalaniz1]

Greetings,<br /><br />I just put together a flounder gigging rig.<br /><br />16 foot Aluminum John Boat. I have a 20 Horse tiller Johnson on it.<br /><br />My questiion is: Is this enough motor to push this rig + two guys (400 lbs.) I can't get it to get up I can only get about 5-10 Mph.<br /><br />The engine seems to run fine but sounds like it is slipping at full throttle. I changed fluid in lower unit, all pins are in and lower end rubberlooks good. I've tried different angle settins on transom. I have 100 PSI in each cylinder and both plugs are sparking good. Is 100 psi good or should it be higher?<br /><br />Maybe Cavitation? Carburation? All help appreciated.<br /><br />The motor is 3-4 years old.

 

[CATransplant]

Re: Will not plane out

If it sounds like it's slipping at full throttle, it's probably the prop hub.<br /><br />OTOH, you're probably underpowered as well for your 16' jonboat. But you should be able to do better than you're doing. <br /><br />Take the prop off and mark the hub and prop with a Sharpie or other waterproof marker. Reinstall the prop and do a WOT run. Remove the prop. If the marks don't line up, you have a bad hub. You can get it fixed.<br /><br />You can't tell by looking.

 

[dalaniz1]

Re: Will not plane out

Thanks for the tip, I'll give it a whirl. Boy was I off on the age of this motor. Ran numbers so I could get Spark Plug.....1973!<br /><br />Man it looks new!