Jon boat outboard not pushing boat correctly. Wrong prop?

[tbrown913]

I have a Lowe 1436 that I decked the front with 2x4 and half inch polyurethane deck (like plywood in weight) and put a seat on. I put down 1/2x6 polyurethane boards in the middle section, and the same boards on the top of the rear bench where I mounted the other seat. I just purchased a 2006 mercury 9.9 and got it installed with a Jack plate so the cavitation plate is within 1/2" of the bottom of the hull. I took it out for a test run the other day and it never got on plane. The back end seemed to be plowing through the water. I got a top speed of 11.2 mph now, i am a 300 pound man, and i had my 150 pound friend in the front. The front of the boat was up, i was not porposing at all. In the boat i only had a 3 gallon gas tank, a lawn mower battery for the fish finder. The rpms really didnt change after 3/4 throttle. Do I need to get a different prop? The only thing I have seen on my current prop is 8.? And it's a 3 blade. I cant tell what the second number on the prop is. Any ideas would be great. I am looking at moving the battery to under the front deck, but it's only like 20 pounds.

 

[1gr8bldr]

I don't think a prop change will be enough. You'll probably need a 20 hp. Once you find the hp to get the boat "on top of the water", it should go, but it's got to get up and glide across the top rather than push water.

 

[Dbender]

T brown, there isn't anything you can do to make it any better other than getting out of the boat. 11 miles an hour isn't bad for all that weight. I'd get a bigger gas tank you'll be using a bunch of fuel.

 

[Ballplayer]

I'm disagreeing with the about the personal weight situation, I have a 1436 Bass Tracker with a 1972 Johnson 9.5 hp., 2 stroke, 3 blade prop,....myself at 225 lbs and a grown 23 yr. old grandson 250 lbs. and can consistantly go 17 to 18 mph., it does take a while to plane but once there your free but I feel it's more in weight distribution and motor trim....balance out the weight better if you can and check your trim and also your engine timing.

 

[little rascal]

I've got 14/36 with 9.9 merc 2 stroke stock 3 blade no jackplate. It runs awesome, surprisingly it will plane out quickly with me 225# and my partner 280-300#, cooler in the middle, full size battery in the back, 3 gallon tank in the back, small troll mtr clamped on the back.
These are non- performance hulls you can't do much except distribute weight where it works best. 4 stroke is a little heavier. Your jackplate put your motor a little further back, that means more weight back past the transom, you may have to reach or sit further back which means more weight on the transom.

 

[1gr8bldr]

Play with the trim as well. If you have any slop in your jackplate, your motor could actually be tilted downward, pushing the rear deeper. I run a 150 Jet on a 24ft SeaArk. Tilt and height play a major roll in speed. However, you need to get on top first.

 

[1gr8bldr]

I epoxied a small round level, on my console. I often ask a rider to move forward or rearward according to how my level looks. I'm not looking for level, I just recognize the point that does the best. Mostly I watch my spray line. The level is actually for extreme shallow water. It floats higher if the entire bottom is flat, rather than the front 4 inches higher than the rear. Point is, that it helps get the boat on plane by a lighter front rather than heavy. LOL, I think of 2 friends that I used to see on the lake. They would pass by motor maxed out, one guy all the way in the front, going about 10 mph, pushing water like a barge. It's hard to tell a grown man that he needs to get off the front. LOL, maybe one day one of them will figure it out