Prop Question

I didn't get on lake of test boat today, but I got a new prop yesterday. I have 1974 Johnson 25 mounted on a 14 foot boat that is 48" on bottom. I haven't been able to get boat on plane. Motor runs okay but had a cracked fuel filter cap. The prop on the boat was a little chewed up--but I've seen worst. The dealer said the prop list for the motor was a 9x10 and that is what I got. When I took off prop it was 9 1/4 x 11. I can take back prop if it totally the wrong one. When I was fishing I had livewell and me in back and fishing buddy in front. I could not get the boat up on plane. The guy at the dock who sealed most of the crack in fuel filter cap with JB weld couldn't get the boat up on plane when he tested it. I was just happy to be able to fish on my vacation, but now I want to figure out what is wrong.

Thanks,
Marion

Not sure with that. Ihave a 1448 with a full deck on the front with a 88 25 suzuki and with 4 people on it, the boat will plane out. Not sure of my prop size. Did you try to put your motor all the way down?

For the trip it was in the second hole. I am leaning to the fuel pump sucking air at high speeds. I should be able to test it tomorrow and I will probably keep the new prop. I never knew that the trim and prop made such a difference.

Marion

Something is definately wrong if that motor won't plane that boat off with 2 people in it. I doubt that it is the prop at this point, because going from an 11 to a 10 pitch prop would actually help you get on plane quicker, not hurt you. It sounds to me like the motor may not be reaching it's normal rpm range.

One more thought:

Is it a long or short shaft motor?

Short shaft and it sits on the boat at the same place as the other one. I still have the other motor(89 'rude) so I could put in back on boat--but I really like the electric start. The whole time I had boat in the water--three days, it started right up(except when the fuel filter cap started leaking really bad.)
If it doesn't run good tonight I will start checking compression and looking at the carb.

It's good to know the new prop will help. I will keep it on motor for now.


Marion

Unless you have that boat extremely overloaded, a 25 hp should plane it with no problem at all. Sounds like you have motor issues.

The ancient 18hp on mine will plane it fully loaded even with a chewed up prop.

I got the boat out and got it up to 20mph on handheld GPS. I think I could get a little more out of it. For now I am a lot happier than last week. I am going to run some carb cleaner through it. I had the motor in the trim hole closest hole to the transom.

Thanks for the help.

Marion