I suspect I have a prop issue, boat lunges to right at high RPM.

[Wayloncat]

I have a 1992 Basscat P2 with a Mercury XR6 150 on the standard 6" CMC manual jackplate. Got the boat 6 months ago, and this is my first bass boat. I had the engine fully serviced and mechanic said it was basically perfect and had very low hours. The boat is also in remarkable shape for it's age. It came with a 4 blade unbranded SS 23P prop. The issue is that at between 5000 to 5800 RPM it gets little to no acceleration. Top speed is 54-55 mph (GPS). And at 5600 to 5800 it feels like the prop loses and regains grip somehow. Speed stays about the same but RPM's jump, also the boat will pull to the right when it loses "grip" but then drives fine when it regains. When this happens to nose of the boat will instantly jump to the right, and can be a little scary sometimes. This has happened since I got the boat. As an inexperienced driver at first I thought it was because I had the trim too high, maybe venting or cavitation. Trimming down does not seem to help. And last weekend it did something new that makes me think that prop is possibly "spun". I punched the hotfoot from a pretty much dead stop, the bow rose as normal but before it planned out the RPM's suddenly spiked to 5800+ as if it slipped into neutral. I let off the gas and tried again and it took off fine. From my research this sounds sort of like a spun prop, but not exactly. Like I said, I'm new to this and any input you guys have would be greatly appreciated.

[Ben Danbleume]

Only time I've had my boat jump to the side it was prop related, needed to be serviced. You might try lowering the motor slightly.

[lpugh]

Drop the motor to 3.5 prop to pad and recheck, very suspicious it is mounted way to high, also consider a 23 p tempest plus, power tech, or turbo prop. Some guys liked Trophys for that rig, I disposed them. Tempest and the old Turbos were my favorites with a 200 in a 25 Pitch

[Wayloncat]

Drop the motor to 3.5 prop to pad and recheck, very suspicious it is mounted way to high, also consider a 23 p tempest plus, power tech, or turbo prop. Some guys liked Trophys for that rig, I disposed them. Tempest and the old Turbos were my favorites with a 200 in a 25 Pitch

Thanks for the input! So I just did a prop to pad measurement. With the pad and cavitation plate leveled, the center of the prop shaft is 4.25" lower than the pad. I'm guessing the previous may probably had the same issue, that's how it was set when I got it. I do plan on getting a Tempest Plus in the very near future. (tax return😊) I'm told 23-25p should work well on my setup. A friend also suggested trying a hydrofoil, but I don't know.

[angle iron]

Thanks for the input! So I just did a prop to pad measurement. With the pad and cavitation plate leveled, the center of the prop shaft is 4.25" lower than the pad. I'm guessing the previous may probably had the same issue, that's how it was set when I got it. I do plan on getting a Tempest Plus in the very near future. (tax return) I'm told 23-25p should work well on my setup. A friend also suggested trying a hydrofoil, but I don't know.

Sounds low.

[lpugh]

Is there anything such as transducers mounted on the running pad in front of the lower unit. They should be at least 16 inches to the to the starboard side of the pad

[zeke4351]

Make sure the motor is mounted straight on the boat

[Wayloncat]

No transducers, motor is mounted is perfectly straight. Everything seems to be in the right place. My current 4 blade prop does have 4 holes behind each of the blades, I'm told they a for exhaust. A friend suggested plugging the the holes and experiment as they could be putting causing exhaust gasses over to flow the blades. In any case I am gonna change props, I want a 3 blade 23P. The Tempest Plus and Fury come highly recommended. But i have looked at the Turbo, and the prices are much better. Any suggestions from the Turbo line?

[Wayloncat]

IMG_0892.JPGIMG_0896.JPGIMG_0894.JPGIMG_0897.JPG
I've noticed a gap of about 3/8" where the around where prop meets the lower unit gear housing. The prop looks like it's been modified. The holes appear to be a modification as one hole obscures stamped lettering and the inside have steel burrs from drilling. Has "Gonzales Propeller 1-96 mod" etched on it. Also looks the thrust washer has been rubbing the rear of the hub. I'm not really sure if any of these things are causing the issue. Perhaps someone has some insight. Thanks again everyone.

[mdtritn21]

That looks like a rubber hub prop so it could be spun and that would cause it to rev high when you punch it. If it is spun it will get worse as you use it so look for a 23" tempest or trophy plus set at 3.5 to 3.25 under pad. http://www.bbcboards.net/showthread.php?t=62660 This will show you how to measure prop to pad to be sure your doing it right. Those holes are vent holes someone bored in the prop but they are not PVS holes so you can't plug them.

[Wayloncat]

That looks like a rubber hub prop so it could be spun and that would cause it to rev high when you punch it. If it is spun it will get worse as you use it so look for a 23" tempest or trophy plus set at 3.5 to 3.25 under pad. http://www.bbcboards.net/showthread.php?t=62660 This will show you how to measure prop to pad to be sure your doing it right. Those holes are vent holes someone bored in the prop but they are not PVS holes so you can't plug them.

Yes sir, that’s a spot on assessment. I took a small flat punch and made a couple of dents on the prop and the brass thing in the hub. Checked it when I got back to the boat ramp and sure enough the dents were almost 180° offset from each other. So it’s definitely Spun. Looks like it’s time for a new prop. Thank you everyone for all the great info. Can’t wait to see how it runs properly set up.

[mdtritn21]

You can have a new hub pressed into the prop you have and keep it for a spare and it's not expensive to have it done.