New to the Forum and Prop Question

Been around engines my whole life (sleds, dirt bikes, trucks) but I am new to this boating thing so I have a prop question. I recently was given a boat with a 1992 Black Max 135 Outboard. It is on a 18 foot Maxum bow rider of the same vintage.

Took it out for the first time over the weekend and it sucked getting out of the hole. There was just no get up go with the boat although when it eventually got up on plane my top speed was almost 45 mph at 4500 rpm. I am wondering if a lower pitch prop would help with getting me out of the hole faster to pull up skiers and wake boarders.

It has a 17 pitch prop on it right now and from what I have learned this is already a low pitch for the engine? Can I go lower as I don't need the top speed I just need some low end grunt?

Or should I be looking at the engine and checking compression and that sort of thing?

Thanks everyone, looking forward to getting in this forum and contributing soon.

Never hurts to check compression. That 135 shares the block size and rpm range of the 150 which is 121 cu in, 2:1 gearbox and 5000 - 5600 rpm range at WOT. You are running around 1000 rpm too low and besides a sloppy hole shot, you aren't doing the engine a bit of good, actually bad for it.

Rule of thumb is about 150-200 rpm per inch of pitch. That says 5". That's pretty drastic. Where did the prop come from? If it was on it you have other problems.

I just ran a Bam Prop Slip Calculator set of numbers using your 2:1 gearbox, 17P prop and 4500 rpm. It said that with no prop slip (and everyone has some) you would be doing a max of 35 mph. I believe that. Throw in what I'd think to be a reasonable 20% slip and your WOT max is 29 mph.

If the engine were rolling 5600 where it should be (upper limit of range at WOT and normal load) with that 17P prop then the numbers would be 45 with no slip and with 20% would be 36 mph.

So either your speedo or your tach is failing you.

HTH,
Mark