jmeng

My dad's looking at a used 35 Classic (single step) with carb. 500s. The owner faxed him a copy of the performance report today. We were suprised to see that the boat had 26" Hydromotives and was turning them 5400 rpm. I had expected the boat to have 28s on it. Top speed was 80. Any idea how it would perform with 28" Hydromotives? Is there any advantage to turning the motors this fast? At 4000 rpm speed was 59 mph and we're hoping this would be improved with bigger props. He was originally hoping for low - mid 60s at 4000 rpm. I'd be curious to know what props other 35 owners are turning.

candyman35

I run 24p Hydro's with only twin 365HP. The prop I like the best is a cut down 26 Bravo1 4 blade. It was tweaked to 25p. The Bravo1's have much better midrange but lose a mph or two on the big end. Most of the 502 classics I have seen have had 26p Hydro's. I thought the rpm range on the 500's was 5200. I think 5400 is a little high but I'm not for sure. I also remember 82-83 mph being the number I was quoted when looking at the 500's in my ‘97. A larger prop will give you better mid range as long as you can still turn it to the proper RPM on the big end.

Happing shopping,
Dan

jmeng

Candy,

Thanks for the info. I'm pretty sure the engines are only rated for 5200 rpm. If he gets it we'll just have to do some prop testing.

No one else has any experience with a 35 w/ 500s?

Tarheel

JMENG,
I have a 2000 35 with carb HP 500s. THe boat came from fountain with 27p props and ran in the rev limiters (5250 Port and 5400s). The performance report from Fountain said the boat was tested with 28p props. We bought a set of 28 hydros and let the 27s be the spares. The 28s still let the boat run into the rev limiter. We had the 27s repitched to 29 and have run those this season. Boat is still in the rev limiter. I consider the 29s to not be true 29s because they were bent from 27p. The base of the prop where the blade meets the hub is still 27p so its sort of a hybrid propellor. The boat's best speed was 84.7 on GPS so far. I'm thinking about having the 28s repitched to 30 to try to get out of the rev limiter. I don't think the boat has much more speed in it without more power, but my wife and I are pretty pleased with the performance.

Remember, if you're thinking about a boat with HP500s in it prior to 2000, you want to check the engine serial numbers to make sure you got the later valve springs from competition cams. Mercury apparently switched in 1999. With my boat being a 2000 model, I was concerned that the motors may have been on the shelf at Fountain prior to the valve spring change. Luckily the motors were built in Mar 2000. Powerboat says that you need change the valve springs at about 140 or 150 hours if you have the old style. Interestingly I had 1998 29 single before the 35 and we never had any trouble with the valve springs.

Good luck on the boat.

Bill

jmeng

Tarheel,

Thanks for taking the time to post. Thats the kind of info I'm looking for. Whats the lowest serial number that will have the new valve springs?

Marginmn

Did your boat come with bravos or Hydromotives? And is your boat a single step or two-step?

Tarheel

JMENG,
On the valve springs for the carb HP500s, the Powerboat article implied it was change in mid-1999 and that a technical bulletin was out on the change. When I talked to Mercury guys in my area that can work on the HP500, they couldn't find a technical bulletin on it. I have since seen a few discussions on the same subject in Hot Boat. I'm sure there are some guys on this site who probably know the real scoop.

You mentioned the boat is a 94 or 95. If you're serious about the boat, I would think a good marine survey with particular interest in the engines is a must. Most banks will require the survey anyway. A thorough survey should detect broken valve springs and any other problems you would expect to see based on engine hours.

The carb HP500 is a good motor. About the only thing you have to do to it change the oil and filter periodically and maybe plugs, distributor cap and rotor once a season.

Good Luck

Tarheel

Marginmn,
The boat (35 Classic) came with 27 hydros that had been tweaked by the factory (you could see the props had been hammered on). While they were matched pretty well on the top end, the engines were both still in the rev limiter. That's what prompted us to try 28 hydros when got a set of back up props.

I was told by the dealer in Greenville, NC, that the X dimension on the 2000 model 35 Classics is a little bit higher than previous years, which might explain why the boat is making a little more speed. I think 86 and change is probably all that's in this particular boat, and we're pretty happy with that for stock power.

Marginmn

That's fantastic performance for a pair of stock 500's. I doubt there are any stock 35's classics who are running any better. I"d be happy if I could just get my 35 to run with 27's. I was also surprised to see that mine came with 26 Hydro's from the factory.

jmeng

Tarheel,

The boat is actually a 2000. So I'm guessing that we will be all right on the valve springs. Not sure where you got that I was looking at a 94 or 95. Might have me confused with someone else. Thanks again for the info.