Prop pitch on a 34 Viper
 

Today I test drove the 34 Viper with the regular 502 motors. The boat was real slow getting out of the hole and the bow would take forever to drop. Is this normal because of the design of the step hull? The boat has 4 bladed props with a 30 pitch . Are these the correct props? The boat also would tend to chime walk at speeds above 50 eventhough i tried different trim settings.

Yep! You have to put the tabs all the way down when coming out of the hole. Once you get the hang of it, you can do a one hand tab up, drive up manipulation of the switches while coming on plane. BillR showed me that one. :cool:

I ran 30's with mine. I had HO's.

Chine walk? Uh, yep! You can control it with a bit of tab. Scrubs speed though.

28's may help the hole shot a little, but you could be up against the rev limiter at speed, and it would hurt your cruise speed some. I never liked the way my old 34 Vyper(99 model) came out of the hole with 30's and I had 500hps.
Are your props rotating in or out?

Actually I was wrong. I did run stock 28's. You can run 30's but they need to be labbed to get the rpms up to where they need to be. The stock props were better for cruise efficiency and hole shot.

I never thought of mine as being real slow (2-3 secs) to bring the bow down. It has HO's w/ 28P Bravos.

But like Macklin told me once, use full tab and the drives all the way down.

Although I usually go about half tab. I also usually go to 1400-1600 rpm for a 10-12 secs before I go up. That gets the speed up, So the transition to plane is alot less like a hole shot.

I made the mistake a few times trying to go on plane with the drives about 3 or 4. Big NO-NO - you see nothing but sky. Duh..

I've had a few knowledgable people on the boat. They all thought it didn't have a problem at all getting out of the water (Formula Guys).

As for the chine walking, I only really notice it over 70, and as said a bit of tab pulls it out.

I am a little confused. Are the 30 pitch four bladed props the ones that come with the regular 502motors?I am looking at buying this used 340 Viper but it seems to be real slow coming up on plane and the bow takes forever to come down. If you try to force it the props start to cavitate. Bringing the tabs down does help but I have never experienced anything like this with my 31 foot Scarab. Any help would be appreciated. Thanks....

It's likely the props. The labbed 30's I tried out would cavitate coming out of the hole if you didn't let them hook up as Shawn mentioned above.

The 28's would hook up much better. I could fire wall those props out of the hole. But never did. Guess that contributed to never having any drive issues with that boat.

Do you think a previous ownre changed the props or did the Viper with standard 502 come withthe 30 pitch prop

Well I run 28 four blades done by BBlades turning in with 500 HP's and it gets out of the whole pretty fast, never been left behind for sure, chine walk on the PQ's above 70 is normal just need one notch in on the K planes, you can see mine run at WOT on U-tube and see they run very strong and straight. I just put mine in the classifieds as well. Looking to go A/T soon !

My 99 came with 30's with the 500hps but the 99 sitting next to it with 502mpi motors had 28's on it. In fact we tried the 28's off of the 502mpi boat because I was so unhappy with the time to plane. With the 28s it would hit the limiters and I just learned to back off just a hair..

My 2000 has 500 EFI's with 30" Bravo 1's but the drives came with 1" spacers. With drives in and tabs down no problem out of the hole. In fact i think it comes out strong.

I also have a pair of 15 1/4 24 pitch 4 blade custom props that ran very strong with no blow out at all, and would snap out of the hole with a top end at 78-80. Just got to play with your set up to find the right prop.

Mine was one of the early 99s that were have hull problems(planing issues), so we tried every combination imaginable(props/rotations etc) I was told by the S.E. P/Q rep that the design changes were ongoing in 99 trying to improve the planing speeds, never was real impressed with that part of the boat, other than that I loved it.

I may try some 28 or 26 pitch props see how it does. With the 30 pitch props i could only get 66mph.I am not familiar with the Powerquest hull but I would think that the boat shold be quite a bit faster. My 31 Scarab with no step hull and 330 hp motors will run 62mph with 23 pitch props. I have friends with 35 foot Fountains and Bajas that have the same motors as the Powerquest that I am trying and are running 26 and 28 pitch props. I know that their are differences between hulls but I wouldnt think that I would be so different to warrant the 30 pitch props. All the mphs were done on gps.

502mpi's don't have enough azz to pull the 30's in that boat I don't think, the 28's should get you up to 70 or a little above, and plane a little better to.

66?! That's not right. Mine would run 78 with the stock 28's, light load and cool air. And mine was the slowest of the three in our club. :rolleyes: The HO's are what...10 more hp per side than the 502's?! Dude, you need to figure that out before purchasing. That boat should be in the low to mid 70's I would think. That is if that boat has the newer, faster hull. Not sure about that.

A run with different props is a very good idea. Keep us posted.

Oh, I see it does not have 502 mags. What is the hp on those motors?

The 502's are the 415hp. I would still think it would do better than 66mph. The 340 is a 2000 with the step hull but I don't know if its the first generation?

Allrighty then! My last statement stands. Start with a good set of stock B1 28's. If the dealer wants to make a sale he should be more than happy to oblige.

Low to mid 70's at least with the 28's,,,66 with the 30's I can see, especially if its costing you 3 or 4 hundred rpm's. It ought to be a real slug coming on plane with the 30's.

28's should be the right prop assuming they have not been modified. I had 30's labbed by Merc and could get 83 mph on GPS but it was much slower to plane. With 28's getting to plane is not a problem. Just tab down/drives down and give it some gas but don't fire wall it.

TTT. I saw your post in the tech forum about the 502's. You need to try a smaller set of props to see if this boat will run! Then start worrying about the engines!!

Thanks for the reply I will take your advice.