Pontoon Boat & Deck Boat Forum

Friend of mine recently purchased a used 15.4' bumble bee bass boat with a 75hp 2S... he can't get it to plane out with two people in it...

Says it would plane out with him alone.... but when his dad was with him... it would not... both men probably weigh 500# combined...

What's the fix with the added weight?

He says he tried everything with the trim to no avail...
Also, it has a hydro foil and a manual adjustable jack plate...

Any suggestions...?

My father in law had almost the exact same problem. He has an older 17' Performance fishing boat. I went through the entire fuel system, compression was good, firing was good, prop was good. Everything mechanical checked out fine.
On his, it has a drain in the floor, which drains into the bottom of the hull. There is another drain that drains this water into the rear bilge. I found that the drain from the hull to the bilge was stopped up. After I drained probably 50 gallons of water out of it (probably mostly rain water, as he doesn't cover it) , it ran like a raped ape !!

Woody... Thank you for the input... I appreciate it... I asked him... he said he checked it and it's dry... another fella suggested the prop may be the wrong pitch... not sure how the prop pitch could cause the boat not to plane out with extra weight in it...

What RPM are you getting with two people in boat. That will tell you alot about what is causing the problem.

brumbyvet wrote:What RPM are you getting with two people in boat. That will tell you alot about what is causing the problem.

I asked him... he said he thinks it was between 3000 and 4000 but can't remember for sure... obviously if that's the case his prop is probably way too big... our 2stroke max rpm is 5600 and that's exactly what it turns with a light load and good conditions...

I didn't think to ask him max rpm... thank you for the input.... he said he will take it back out and see what his rpm at wot is... I'll keep you posted...

What should a late 80's early 90's Mercury Mariner 75 hp 2S max rpm be?

My dad has a 1987 17 foot fish and ski with a Mercury 50 on it. It won't plane either and the rpms are only getting to about 2k. Carbs were just rebuilt. Prop is correct. I have heard that there is two parts to the ingnition. One for low rpms and one for high. Anyone know anything about that?

He needs to drop the prop pitch by 2.

He's gonna take it back out Saturday morning and find out for sure what his WOT rpm is with him alone and again with him and his Dad... I'm curious

I have to agree with the too much pitch post. I've seen it before. drop the pitch a bit and the motor will turn up and get on step. from My experience.

RcgTexas wrote:I have to agree with the too much pitch post. I've seen it before. drop the pitch a bit and the motor will turn up and get on step. from My experience.

DWRAT wrote:He needs to drop the prop pitch by 2.

Found the same info in my owners manual today looking for something totally unrelated...

Basically said exactly what everyone has been saying already... check the bilge for water... make sure it's loaded properly. .. can't reach max rpm reduce prop pitch... mercury book even has the prop sizing information...

Thanks everyone for your input... we appreciate it.

I'm excited to hear from him on Saturday to see what it turns...

DWRAT wrote:He needs to drop the prop pitch by 2.

That's exactly what he's gonna do... drop the prop pitch by 2...

He got to take it out today after work... ran 4400 WOT...

Finally got it to plane out... thinking his trim has intermittent issue... possibly wasn't trimming down...

Thanks for all the help... we appreciate it... learned a few things dealing with this...

Maybe the lard ass just needs to drop a few pounds?