Ski Nautique 1979 Prop Question

Hey Guys,

I'm new in this Forum and read a lot of helpful things about my old Ski Nautique. It's a 1979 Ski Nautique with a OMC 350 (260hp) in it.

Now I have a question about my Prop. Actually there is a 13RH14 on it, I hope you can see the Picture..



She ran max 4200rpm and goes max up to 68 kph, so I think that isn't enough for this Engine. What is the original Prop for this Boat and what kind of Prop ist good for Wakeboarding? I read a lot about ACME and OJ Props, but don't know which of them is the best for me.

Thanks an greets from Germany

Benni

Benni welcome to CCFan first of all and lets see some pics of the 79 SN. Always cool to see pics of a new members boat and bonus points when it's a European member.

If wakeboarding is your primary use of the boat then I'd say you should go with the ACME 542. It's a 11.5 pitch prop vs. The 540 which is 12.0 so the hole shot would be a little better especially if your weighted down for boarding..You'll sacrifice some top end speed but that doesn't seem to be what your searching for.

I am also a little alarmed by the 4200 max RPM. When is the last time plugs were changed, cap and rotor and timing checked. Wow as Hollywood said, check out the prop, it is at least 2 inches from the strut, I don't think I have ever seen one like that - very interesting.

Agree with all of the above... 4200 is low and probably the result of the too-large prop. I would think that 4200 with a 13x14 would push you faster than 42mph though... So something is amiss. Either inaccurate tach, speedo (GPS?) or a worn out prop. Either way, 540 is the hot ticket and should allow the engine to turn in the sweet spot for best performance (4600-4800). A 542 on that hull should not be necessary unless you're running a LOT of weight, ALL the time.

Do take the opportunity to check out the rest of the drivetrain... 2" of prop to strut clearance is excessive, though not necessarily uncommon from the factory. If your shaft is half way out of the coupler, now would be a nice time to realize it! Keeping that clearance below an inch (ideally ~1/2") would be best if you end up replacing/repairing components.

NICE looking Ski Nautique! Another Team Red boat!!! I am guessing that bottom paint is definitely NOT helping on the top speed thing.

Kristoff will have to let us know if Mann Filters are better then Fram!!! (Benni27 - thats a joke you will learn to understand, the topic of oils and oil filters become pretty contested around here - HA!)

Go TEAM RED!

Yes, that bottom paint can't be helping your speed and you need to get a timing light on it and double check your points gap.

Digging the wacky extended pylon paint scheme...Groovy baby Yeah!

storm34 wrote: Upside down valve cover is good for atleast -2mph as well. Welcome to the site!

Maybe not Chris - It's a RH engine so you need to be able to read the text from the starboard side.

Nice boat, what lake are you on?

Hey Guys,

today I checked the timing and set it to 8° after OT, this is where she ran's ok (without gear fires up great, in gear max 3900-4000) What is the correct timing for the OMC 350?

There is a Petronix Ignition:

Too much prop for sure. The bottom paint wont be a measurable difference on this class of boat, just fugly.
My 350 Chevy on a 1979 SN is making about 280 or so ponies and I run a 13 / 12 ACME to 4850 and 49 MPH (gps) with the final timing set pretty conservative at 10* initial and 28* full advance. Left hand though... Im a bit baccereds.