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-   -   Prop Slip Where to start Diagnosis (https://www.offshoreonly.com/forums/do-yourself-boating-budget/319196-prop-slip-where-start-diagnosis.html)

stimleck 10-17-2014 12:55 PM


Originally Posted by AllDodge (Post 4204724)
Was this a complete turn key 502, carb, distributer, computer everything, or just a long block?

Is it an EFI or CARB

4 blade equal to 2 pitch larger, not that I've ever heard. Only thing a 4 blade will do is give you more lift, but also more drag from the extra blade

HI It was purchased as a complete motor. It has a Holley 800 cfm carb which I had rebuilt and set up by one of the local legends because it sat for a year with fuel in it. I replaced the MSD marine ignition with a new unit because it was faulty, new msd blaster coil (because its cheap) and new cap. I didn't change the billet msd distributor that was in the boat but I do plan on changing the magnetic pick up for 2015 as its slightly rusty.

stimleck 10-17-2014 01:02 PM

I tried an offshore 4 blade which is a knock off of the bravo 1, unfortunately before I did a top speed run I hit a rock ( 1 hour after putting on the prop) and ended up buying the prop lol.
Because of the prop shops theory that a 4 blade needed to be 2 pitches smaller than a 3 blade to hit the same rpm it was only a 19.
Listening to you folks I think I should be going up.

Originally Posted by Quick2500 (Post 4204457)
Exactly! I was thinking Bravo 1 24p, guaranteed to pull that RPM down and use some of the torque that mill can generate.


stimleck 10-17-2014 01:03 PM


Originally Posted by AllDodge (Post 4204310)
Not knowing what the OP drive ratio is and entering 1.5 as a guess, I think he is not that bad so far as slip. What gets me and the reason for my prior post, is his engine should have about 100 more hp then my Rinker, yet he turns a smaller prop and cannot turn it more then 5000. I have a 19 pitch prop and only use it when I plan to have a fully loaded boat out for an outing. I'll over rev with the 19 when it's just 4 folks

Sorry should have included that the gear ratio is 1.50

stimleck 10-17-2014 01:05 PM


Originally Posted by Quick2500 (Post 4204435)
I believe about 5000 rpm is the top end of mercs wot range on that engine and I think it's rev limiter is 5050. You are probably just sitting on the limiter. Prop it up until you are getting 4700-4800 wot and then run the numbers.

I think that is great advice, Like I said the prop shop guy recommended trying to find a fit that would allow 5000 but although they are pretty much the best prop shop in Canada they do not by any means specialize in performance props like B Blades

stimleck 10-17-2014 01:12 PM


Originally Posted by lil red (Post 4204760)
Why are you using such small diameter props? Those are meant for outboard boats and light bow riders. Use a mirage+, a bravo or a rev4 as a baseline.

Hi because the boat came with a 19 that revved out I went to a 22 Enertia and couldn't pull more than 50 mph at 4750 rpm, so I went down a pitch only to learn that the speed was the same but he revs were higher. You guys are clearly correct because the Marina that built the engine recommended 4800 WOT and 5000 max rpm

stimleck 10-17-2014 01:17 PM

Hi no I haven't weighed it but always felt like it must be more than the 4500 lbs advertised weight. I had it surveyed and it came back with low moisture readings. My previous boat was a sopping mess of soaked foam that I replaced the floor and transom in so I was careful this time.
There are two non accessible areas on each side of the fuel tank enclosure which I intend to have a look into this weekend as I pulled he tank for cleaning this winter. There is a possibility that there could be some wet foam in there but I am pretty sure it would have shown up on the hull readings and boats over 25 feet are not required to have flotation foam. (I think)
Is there a simple way to weigh a boat on a trailer and isolate the boat weight from the truck and trailer or is it simply a matter of weighing the entire rig and doing the math?


Originally Posted by Quick2500 (Post 4204795)
Here's another thing. Has the boat been weighed recently?


tommymonza 10-17-2014 01:22 PM

Have you laid a 6 foot straight edge on the bottom yet to check for a bad hook?

stimleck 10-17-2014 01:28 PM


Originally Posted by Quick2500 (Post 4204790)
Or maybe the op is just trimmed all the way down.... And he has a 1.65 ratio....

After my 7th or 8th boat the one thing I know is how little I know, spending this last year reading OSO taught me that. I think I fall in to the group of 98% of boaters that have about 10% of the knowledge of some of the great marine minds but I do understand trimming out. LMAO,

My name is Billy Tucker not Silly Phucker (or Phil)

Actually back in 94 I had a couple of on water lessons from Tommy Hofstetor when he built our 38 Scarab in 1994. If you think I am green you should have seen us 4 twenty year old's with a 38 scarab that we thought was going to be a world beater for 25 k in upgrades. We each had little lake boats and pooled our money to buy an 86 38 kv with twin 330's. Wanna talk about a dog and a bunch or dumb asses.

stimleck 10-17-2014 01:31 PM

1 Attachment(s)

Originally Posted by lil red (Post 4204787)
You experts carry on....

Not sure what this post means but I'm happy to get advice, by the way I posted this in the Classic Offshore section, thought you would appreciate it. I saw it in a local Marina a couple of weeks back.
[ATTACH=CONFIG]531148[/ATTACH]

Quick2500 10-17-2014 01:56 PM


Originally Posted by stimleck (Post 4204821)
After my 7th or 8th boat the one thing I know is how little I know, spending this last year reading OSO taught me that. I think I fall in to the group of 98% of boaters that have about 10% of the knowledge of some of the great marine minds but I do understand trimming out. LMAO,

My name is Billy Tucker not Silly Phucker (or Phil)

Actually back in 94 I had a couple of on water lessons from Tommy Hofstetor when he built our 38 Scarab in 1994. If you think I am green you should have seen us 4 twenty year old's with a 38 scarab that we thought was going to be a world beater for 25 k in upgrades. We each had little lack boats and pooled our money to buy an 86 38 kv with twin 330's. Wanna talk about a dog!

Not trying to be a jerk, just had to ask.


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