I've got a Mako Pro Skiff 17 with a 60 hp merc 4 stroke. Getting out of the hole, I'll hear (and see) my rpms jump up then back down, just for a split second, up then down, until I get up on plane. I see this especially in rougher water. My thought is that I have some cavitation on the prop, or something along those lines. The outboard runs flawlessly other than that so I don't think its a fuel pump or injectors or anything along those lines. I've recently changed the fuel filter, spark plugs, always keep stabill in it, etc...

Anyone have any insight on that? Is this normal? I have a 13p 3 blade stainless Fury prop on it. Any thoughts are appreciated!

That motor needs some exhaust venting to help it spool up and go. So what you’re describing is what it should be doing unless it’s blowing out and setting down.

You can always test it by sticking a piece of duct tape over the vent hole and see what happens.

It isn't blowing out and setting down, so I'm assuming that's good. Thanks for the insight

If your prop stays hooked up solid with the water, once on plane and no other issues with it blowing out like while turning, or the bow of the boat not lifting good and porpoises up and down as like the prop loosing a bite, I wouldn't mess with it.

Otherwise, you might have the engine mounted a little high. If you find you have to run the engine with a lot of negative trim to keep the bow of the boat from porpoising, the engine can be dropped to help this, lots of the skinny water rigs run special 4 blade props with added cup to help address this issue as well as come out of the hole good with little to no bow rise, so they can get on plane in 12" of water.

I like to use a good cavitation plate addition to this, not talking about the plastic whaletails as those are called, I like to use Bob's Machine cavitation plate. These really help with several issues and look good. Bottom line the skinny water rigs are very sensitive to setup, you then add the extra weight of a 4-stroke to the tail, they get even more finicky, not a bad thing really, there are things you can do to help address them.

Do you think it could be a spuned hub in prop

Absolutely it can. Yank the prop off and look at it up close. If this has the new style hub you will see all the slippage, if this the old solid rubber hub your looking for the rubber squirting out around the splines bushing, look at both front and back sides of the wheel.

If it's the prop, you will be able to see signs of this.

Doubtful, if it was a spun hub it would be doing it more then just getting on plane

No. It wouldn’t un-“spun” on pad. They slip once….they’re cooked.

You guys are talking about Mercury's new style hub, the older solid rubber hubs and like a 60hp 4-stroke they will cripple along, I have even crippled 200hp plus ob's back to the trailer. I figure OP has his setup issues, there are some really tricky thinks to get some of the skinny water boats to come out of the hole and do it with little to no bow rise.

Someone was or is selling the same boat and motor in a ad says, quick holeshot

I don't think there's anything wrong with what he's got. Four strokes need to slip to get enough horsepower to get going. He's not cavitating, it's just revving up.

Pat,

Your probably exactly right. Those skinny water boats are finicky with a little 60-70hp 2-stroke on the tail of her, the weight is about half that of the 4-stroke he has.

Well thanks fellas! I pulled the prop to check the hub - all in good shape. It probably needs some adjustment on height of the motor mount, but I'm not going to mess with it. As long as something isn't wrong, I don't mind it. I just didn't want to be negligent if the motor was trying to tell me something that I wasn't in tune with, causing preventable issues down the road.

I don't fish in 12" of water, so I don't really mind it. I fish freshwater lakes exclusively and have been really impressed with the rig. It's just perfect for what I do, where I store it, how many folks I fish on it, how stable it is, etc...

Thanks for the input fellas. I really do appreciate it!

Make sure the motor is tucked all they way down .