Propping questions?!

Hey all,

I have a 1999 Rinker 232 and my wife will not let me get rid of it because she LOVES the seating arrangement. The boat has the 5.7l in it with an alpha drive. I live in Colorado at 5,000 feet and I am having huge issues with performance. I have replaced the outdrive with a 2.0.0 gear ratio, bought a highfive 17p prop, put a 4bbl Rochester Electro choke carb, and a cross plane oversized polished aluminum intake manifold and still top out at 34mph. My tach is only hitting 4200 rpm (when on absolute glass and trimmed perfectly) and my hole shot is only good with less than 4 people in the boat.

I know the simple answer is to just get a 7.4l motor put in, but I do not feel like investing another absurd amount of money if I am doing something wrong. I know that I need to have the RPM between 4600-4800 but it is literally impossible unless I switch to a four blade prop because highfives bottom out at 17p. The ONLY way so far that I have been able to get a good whole shot was switching to a highfive and if I move to a 4 blade I am afraid of losing the hole shot.

I know I cannot be the only person in Colorado with a heavy *** boat with a 5.7l engine, does anyone out there have a simple fix that I am missing?

Re: Propping questions?!

I would say your outdrive gear ratio iS to high for thr 5.7!

2.0 is more geared for a V-6

Need more like a 1.50 ratio for the V-8.

The Prop guy's may be able to help ya!

Re: Propping questions?!

Assuming all of the engine mods are working properly, you're still overpropped.

I'm not a big fan of the high-5 on heavier boats. It's small diameter just doesn't give enough "oomph" to get a heavy boat out of the water. I'd try a 4 blade of at least 14" in diameter and see if that doesn't help. You need to get your rpm up into the recommended range; that'll help as well.

Just out of curiosity, why did you swap the carb/manifold?

Re: Propping questions?!

Moved to prop section where it belongs

Re: Propping questions?!

bladzalot said:

Hey all,

I have a 1999 Rinker 232 and my wife will not let me get rid of it because she LOVES the seating arrangement. The boat has the 5.7l in it with an alpha drive. I live in Colorado at 5,000 feet and I am having huge issues with performance. I have replaced the outdrive with a 2.0.0 gear ratio, bought a highfive 17p prop, put a 4bbl Rochester Electro choke carb, and a cross plane oversized polished aluminum intake manifold and still top out at 34mph. My tach is only hitting 4200 rpm (when on absolute glass and trimmed perfectly) and my hole shot is only good with less than 4 people in the boat.

I know the simple answer is to just get a 7.4l motor put in, but I do not feel like investing another absurd amount of money if I am doing something wrong. I know that I need to have the RPM between 4600-4800 but it is literally impossible unless I switch to a four blade prop because highfives bottom out at 17p. The ONLY way so far that I have been able to get a good whole shot was switching to a highfive and if I move to a 4 blade I am afraid of losing the hole shot.

I know I cannot be the only person in Colorado with a heavy *** boat with a 5.7l engine, does anyone out there have a simple fix that I am missing?

Click to expand...

Ayuh,.... Welcome Aboard,... Not sure on what carb, 'n intake ya got, but they could be yer problem....
To Big maybe...

Are ya Sure it's a 1.98:1 gear ratio,..?? never heard of 2.0.0

I think you've got a problem with the motor's set-up, 'n tunin'...

A 350 turnin' a 17" prop through 1.98:1 gears should run 4800 rpms, bolted to a concrete dock....

Re: Propping questions?!

Sorry about posting to the wrong section, I am new here

Gears are actually 1.62R, prop is a SS High Five in 17p, 4bbl Rochester Carb, Vortec 5.7L Engine, and my Polished intake manifold is a dual Plane.

Like I said, my hole shot is okay, top speed is really low and I am at 5,000ft altitude. It just seems that even at high altitude, for all the tweaking I have done, it should be like greased lightning, but it is not. My mechanic is the one that made all these recommendations, and he has been a certified mechanic in Colorado his whole life, so you think he would know, but I am just stumped to why I am not getting the performance I would expect.

Sorry about the 2.0.0 ratio mistake, he pulled my 2.0.0 off and put a 1.62R on. I bought the boat from Florida so it was all set to run at sea level.

Any other ideas?

Jason

Re: Propping questions?!

bladzalot said:

Any other ideas?

Click to expand...

What octane fuel are you running?
Is your air cleaner clean?

I had to prop my 115 down for running at 5,000 feet plus. A 15 pitch works great at low elevation, but I have to run a 13. Works best at Pueblo and Horsetooth, not as amazing at Dillon.

Re: Propping questions?!

bladzalot said:

Sorry about posting to the wrong section, I am new here

Gears are actually 1.62R, prop is a SS High Five in 17p, 4bbl Rochester Carb, Vortec 5.7L Engine, and my Polished intake manifold is a dual Plane.

Like I said, my hole shot is okay, top speed is really low and I am at 5,000ft altitude. It just seems that even at high altitude, for all the tweaking I have done, it should be like greased lightning, but it is not. My mechanic is the one that made all these recommendations, and he has been a certified mechanic in Colorado his whole life, so you think he would know, but I am just stumped to why I am not getting the performance I would expect.

Sorry about the 2.0.0 ratio mistake, he pulled my 2.0.0 off and put a 1.62R on. I bought the boat from Florida so it was all set to run at sea level.

Any other ideas?

Jason

Click to expand...

That makes a lot more sense.

The high altitude gear ratio option was usually the 1.81 gearing on gen II alphas, so you've got that working against you. A gear change would help.

I'd still recommend something other than that high 5 prop. It's only 13 1/4" diameter, so the thrust column is a bit small for the size/weight of your boat. They generally used a Mirage + on that boat which is 14 5/8" in diameter....so it moves more water.

Again, assuming your engine is running right with the different carb and manifold, I'll throw out 2 options:

1. Reprop. This will be the cheapest option. A Revolution 4 (4 blades) will give you a better holeshot, but a Mirage + will give you better speed. Either is available down to 15" of pitch.

2. Change to a 1.81 gear ratio. This will also necessitate re-propping, but you'll have more options as you won't have to go with such a low pitched prop.

You're not alone here. I lost 400-500rpm moving from 600' elevation to 4300' elevation and had to go through the prop selection process all over again.

Re: Propping questions?!

For what it's worth; using the 1.62 gear ratio, the Mercury prop selector comes up with two choices that seem viable.

First the the aluminum 16 X 16 3 blade.

Second is the aluminum 15 X 16 4 blade.