Bravo II Prop Slipping, Bad Hub? - Maxum Boat Owners Club

OceanStateTuning · 07-29-2013, 05:53 PM

When trying to plane out my Port engine (1998 Maxum 3000SCR, Twin 4.3 / Bravo II) seems to vary the RPM a bit, engine shoots right up to around 4000rpm and then fluctuates a 500-750rpm difference, I first thought it was cavitation but then read a lot about the Hubs going bad. This is my first year with this boat but this problem only started happening recently. I have not hit anything and my props look fine. I do not have a trailer to yank the boat out and its close to the end of the season so would like to try an in-water repair if possible, IE. Changing Prop.

First does anyone know what props should be on this boat? I know they are original as I am the second owner, if I could just buy a new prop to try that would be easiest.

Are the hubs removable? I have a press so I would assume if they are not bonded in that they are just pressed in. I can find bravo 1 prop hubs but nothing on bravo 2.

My buddy has a bunch of extra Stainless Bravo 1 props, is the prop hub/exhaust all same locations and maybe I could just put one of his of a similar size on to try it to rule out the bad hub/limp around until I get the correct prop?

Thoughts?

pascavone · 07-29-2013, 06:03 PM

at the dock, with the engine off and the drive in gear, reach down and try to turn the prob by hand, turns-bad, no turns good.

if bad,

stick your head behind the engine with a flash light and look for aluminum and rubber shaving laying all over the steering lines.

if you see this, your engine coupler is sheered, as it is a rubber donut with an aluminum sleeve which attached to the fly wheel.

They last about 10 years, and the engine goto come out to replace.

this is why people sell boats...

CountryME · 07-29-2013, 09:27 PM

Per maxumcustomercare.com, your boat has the following original props for that set-up:

P/N 51728 18-1/4 X 19 RH PROP 1.0 EA
P/N 55066 18 1/4 X 19 LH PROP,ALUM 1.0 EA

Good luck finding your problem. The hub sounds like the most likely culprit, but PAS may be right with the engine coupler. Keep us apprised.

-JP

mmwjr · 07-29-2013, 11:24 PM

Yep either hub or coupler. I spent $150 5 years ago having a new hub installed but that included a complete prop check as well. Blades were in good shape no nicks.

OceanStateTuning · 07-29-2013, 11:35 PM

Quote:

Originally Posted by pascavone

if you see this, your engine coupler is sheered, as it is a rubber donut with an aluminum sleeve which attached to the fly wheel.
They last about 10 years, and the engine goto come out to replace.
this is why people sell boats...

I might shoot down to the Marina tonight, Boat is pretty underpowered, any more then me and my wife she wont plane easy and if a engine has to come out, it sure will be being upgraded to atleast a basic SBC. Hopefully its not this, IF it is, never seeing one before, how long would they last being easy on the boat before that drive wont turn anymore? I assume it is just a rubber bonded to metal like a Harmonic Balancer, and once they spin they can just come right apart with no sort of safetys/locks or anything to keep em spinning.

OceanStateTuning · 07-29-2013, 11:37 PM

Quote:

Originally Posted by mmwjr

Yep either hub or coupler. I spent $150 5 years ago having a new hub installed but that included a complete prop check as well. Blades were in good shape no nicks.

Obviously I am hoping for this, I have not smelled anything burning except one day, before this happened, but turned out to be my blower fan melting out of its body.

OceanStateTuning · 07-29-2013, 11:38 PM

Quote:

Originally Posted by CountryME

Per maxumcustomercare.com, your boat has the following original props for that set-up:

P/N 51728 18-1/4 X 19 RH PROP 1.0 EA
P/N 55066 18 1/4 X 19 LH PROP,ALUM 1.0 EA

Good luck finding your problem. The hub sounds like the most likely culprit, but PAS may be right with the engine coupler. Keep us apprised.

-JP

Awesome! Thanks for the info! Looking through this site now for any other useful info!

Would the LH Prop be on the Port Engine?

Painter · 07-29-2013, 11:54 PM

When the splines on your coupler wear to a point they will then sheer off and their done. If they have sheered off, there would be no way you could get that boat on plane with a single 4.3. The coupler won't slip from splines or rubber failure it will just not turn your drive at all.

pascavone · 07-30-2013, 05:25 AM

i've never heard of a 3000 scr with V-6's before.

Spiking RPM is coupler slip.

The rubber donut is to kill vibrations in from the engine, and is a pressed fitting.

If its a aluminum failure, its too many bottom strikes.

If a rubber failure, its a miss align engine to drive, which means the engine motor mounts need to be adjusted.

The good news its the new couple is a $400 disk that just bolts to the flywheel, and if you have an A-frame, you could raise the engine out to replace.

They make a steel couple upgrade, that has more splines so, any problem would result is a broken U-joint in the drive.

Painter · 07-30-2013, 07:09 AM

A miss aligned engine can take out aluminum splines as well. The rubber portion of the coupler is vulcanized not pressed in place. And the upgrade to steel coupler has the exact same number of splines as the aluminum, it is recommended for low rpm work applications or high performance. And lastly you would most likely destroy some gears before a u-joint broke. Also if its a strike and it takes out your drive it's covered under you insurance, but they won't cover a coupler failure.

mmwjr · 07-30-2013, 12:43 PM

I have never heard of V6's in a 3000 scr nor have I heard ov V6's with BII's.

Painter is dead on regarding the coupler.

The coupler is there to protect the engine incase the outdrive were to lock up. The hub on the prop is there to protect the outdrive when stricking the bottom.

pascavone · 07-30-2013, 12:55 PM

Agreed,

I installed the steel coupler when i replaced mine, it has a 4" spline socket that is forward of the flywheel face.

Before I replaced it I would be on plan and give it throttle, and the RPM would raise but the boat would not respond. Boat ran fine under 23 MPH, but any load and it was like driving a car with a slipping clutch.

Swinging a 7.4 out under a radar arch is not something you want to to twice, so I also rebuild the transom pin assembly, as those seals are shot after 10 years.

If you buy a boat $10k under market there is a good reason.

Rather start fresh, and get the full life out of it, and not worry about it again.

shrew · 07-30-2013, 03:28 PM

I've seen a 1998 3000 with twin 4.3's. I don't recall what outdrives they had on it. The engine compartment had a ridiculous amount of room and I like the cockpit setup better than the 3200.

pascavone · 07-30-2013, 04:00 PM

had to google it for myself, and your right..... 10,000lbs on 2- v6's?

wonder if it was a special order?

Good news, lots of room to pull the engine forward to change the coupler.

CountryME · 07-30-2013, 04:51 PM

Hey PAS, is that a 100% clogged riser in that picture too? Or was it stuffed with a rag to keep it clean?

pascavone · 07-30-2013, 08:30 PM

its an old riser which i replace in my 2nd season.

amusing, that the previous owner installed a new long block, and a new bravo III out drive, but left all the old parts on it, which after 10 years had to be replaced.

OceanStateTuning · 07-30-2013, 11:01 PM

Quote:

Originally Posted by pascavone

Looks just like my engine bay, tons of room in front but to way to pull straight up, you have to go forward a bit then up but I don't know how you would get by with the Arch? Ideas?

OceanStateTuning · 07-30-2013, 11:06 PM

So I went to the Marina, lifted drives, reached wayyyyyyyy under as I put the swimplatform.com extended platform on it and can just about reach the props, both props spun in gear, put them in/out of gear a few times and the props will spin one way but not the other, not sure how much force needs to be on them to check but I gave it everything I had with my fingers and neither port nor stbd turned. Maybe I need to take the boat out to good water and jump in and try to spin them with both hands?

I looked under engine and instantly saw rubber on both engines BUT it is just in the belt line and all over front accessories so I guess my belts are slipping. Nothing under my Port engine (one giving me issues) but the Stbd had a bunch of crap under it, mostly some oil and stuff so was hard to tell, I need to clean my bilge! Was just looking by the bellhousing area.

mmwjr · 07-30-2013, 11:29 PM

You need to look at the back of the engine where the coupler is for signs of rubber that would indicate the coupler is shot. Do you have spare props to but on to see the problem goes away? Other than that you can send the prop out to be tested, most places can turn it around in a week.

OceanStateTuning · 07-31-2013, 12:28 AM

Yeah I was looking around the bell housing, did not see anything on the bilge under the engine, maybe I need to look ontop of engine, hard to snake myself behind it to see, under it there is plenty of room. No spare props and at almost 400$ for a guess I might be better off sending it out to have checked, OR maybe I could scribe a line on the prop and prop nut and see if it moved, not sure if the nut/washer will scribe though.