Do I have blow out?

[mrsturggie]

95 181 dc 175 3 1/4 prop to pad 6inch jp. My boat at about 3/4 throttle to full throttle and trimmed out will occasionally get suddenly squirrely from the rear completely out of now where. It happens for just a split second, seems like it kind just lets go so to speak and the rpms come up a touch.Doesn’t seem to matter what prop I’m using either. Usually run at tempest plus 24 that’s stock or a merc high 5 23 pitch with all plugs in it and 1/4 holes drilled in them. I can go for a couple outings without it happening then it might do it a couple times next time out. It sure makes ya pucker when it decides to do it. What might be causing this? Could it be too high on the jack plate? I’m asking before I change anything that might make it worse. Thanks for any thoughts you might have towards my problem. Have a great day

[Tx Champ]

Blow out is during your hole shot when the prop loses bite and RPM jumps up (loses traction).

[pmgoffjr]

High speed blowout will happen with a merc lower unit at about 86 mph. I promise you're not doing high speed blowout.

First question, do you have anything whatsoever hanging off the bottom?

[mrsturggie]

Absolutely nothing. Stock lower unit. When this occurs it almost seems like I hit something if that makes sense. I’m positive that I have not hit anything. And as I have said before it does it with both props I use. I have a friend with a 19ft champion fish and ski who has the same issue. He runs a trophy on a 200 opti. Nothing on his transom either.

[grout-scout]

You don’t have an external transducer on the port side?

[pmgoffjr]

I know exactly what you're talking about, I had a couple different boats that would do it also. It's a little startling when it happens.

The cure is probably come down a 1/8" that's what I did to fix it, the real pros determined at too high the prop would sometimes slap the water instead of cut it, which created a air bubble which causes the lurch. Give it a try.

[mrsturggie]

Will do pat. Thanks for the tip. I will report back on the results. I have a manual jp so it will take a couple wrenches and a ratchet to get it done. Going out next Wednesday. Grout scout, I have thru hull transducer for my console unit. Not a thing hanging off my transom

[pmgoffjr]

If you still experience the shift right surprise,look at putting blow out ring on your lower unit, just ahead of the prop. We did that to my '95 202 and it eliminated the shift. But that was happening at 75 ish mph, but regardless you want it gone.

[mrsturggie]

Went out after takin your suggestion pat and I think we may have fixed it. Droppped it 1/8 and it did it right away. So I dropped it 1/8 more and fan the hell out of it without anymore issues. Slowed her down a bit but that’s better than the surprise factor at least to me. Thanks for your help. Have a great day

[pmgoffjr]

Glad it worked. Go catch some fish now!