Spun Prop??? I'm not sure....

[nlma1995]

'93 Rinker Captiva 209 BR
4.3L LX
Aluminum 3 blade 14" dia x 19 pitch prop

I'm not sure what might be wrong.  I had just powered up and gotten on plane with my trim at full down position.  I began to trim the motor up to get to my "sweet spot" when I heard a grinding sound with an instant loss of power.  I thought maybe I trimmed the motor up too far so I quickly trimed it back down.....the noise stopped and everything seemed fine.  I trimmed the motor up again and same result.  For the rest of the day after that, the RPM to speed ratio seemed off.  Using a 3 blade aluminum prop, 19 pitch normally I cruise at about 30 mph at 3800 to 3900 RPM.  After the Incident, I was running about 30 Mpg at 4200 to 4400 RPM.  I still have a good hole shot from stopped and can get on plane without any problem, but the higher RPM at cruising speed the R's seem high.  Before it happened, we had been running for about 2 hours straight, so I thought maybe my outdrive was possibly overheating so we beached for a while, let the outdrive cool then headed for the dock.  The boat seemed to run normal for about the first 15 minutes then without moving the throttle, changing the trim or anything, the Tach started to creep up from 3800 to 4400 RPM's all by itself.  Is there a possibilty of the Tach being bad?....I'm at a loss. 

If anybody has any idea what may be happening, I'd appreciate some feedback.  If I'm missing information, please let me know and I'll add it.
Thanks Rinker clan!!

[HALL'N]

I doubt if you spun the hub or you wouldn't be able to get ot of the hole. You didn't get into a sandbar did you?
I don't think it's a heat issue or it would be slowing rpms and speed.
You might have a small twig or some leaves caught on the front of the cavitation plate that would cause it to rev higher. I've pickup small tiggs etc. before the will usually cause the prop to "blow out" and scare the crap out of you. The more I've thought about it I'll bet that's what you've got going on.

Keep us posted on the outcome.

[frodo13056]

Could be that you may have spun the engine coupler or it's on it's way to going bad. The engine coupler is an aluminum piece that goes between your lower unit drive shaft and the engine and the coupler splines are the weak link between the engine / lower unit. It needs to be routinely greased via Zerk fittings at the back of the engine / lower unit drive shaft. Since the coupler is a softer metal than the hardened steel lower unit drive shaft splines, if/when the splines go dry (no grease), it's only a matter of time before the hardened steel splines cause excessive wear on the coupler and next thing you know - the coupler is shot.
Usually, when a coupler goes, you get a pretty noxious odor at the rear of the engine which smells like cooked bearing grease / kind of a rubbery smell.
Bad news is that if it is the coupler, you'll have to pull the drive and the engine to replace it.

[AlexisandChad]

My cav plate was bent when I got the boat.  This happens to me at least once a year.  Get a twig caught and while trimming out I get the growl.  When your at the dock, pull your drive all the way up and run your hand around the cav plate.  You might be surprised what will be around there. 

[nlma1995]

To check if something is wrapped up on the prop, do you think it is easiest to pull the prop off?

I'll do that tonight and let you all know what I find.

Thanks for the replies.  I appreciate all the collective experience on the site.

Neil

[HALL'N]

If something is wrapped on the prop you'll be able to feel it. I wouldn't pull the prop while in the water you're just beggin' for disaster if you do. Just in case you're unclear on the cavitation plate it's the horizontal flange that goes around the lower unit just above the prop.

[nlma1995]

Hall'N,

Not to worry about losing anything in the water when I take off the prop.  My boat is trailer-ed all the time anyway.  It's safely sitting on my driveway now.
I did check to see if anything was wrapped up on the lower unit when it happened on the river.  I've had  everything from plastic bags to large chunks of barge rope tangled up on the prop before.  Nothing surprises me.  This time though, there was nothing wrapped up.  

I haven't had time to pull the prop yet.  Hopefully tonight.....  

Where do you hail out of in Shelbyville?  We try to get down there a couple times a year.  Neil

[nlma1995]

Well, I took off my prop tonight and found a small wad of fishing line wrapped up around the prop shaft.  I'm not sure if this was the problem or not though.  It was around the shaft between the large washer on the base of the prop, that has the taper in the ID that matches the taper on the shaft nearest the bearing.  Hard to tell if it was causing binding or not. 

I'll let you know  if it made a difference or not.

[bat32]

Sure hope that was it.  You heading out this weekend?

[nlma1995]

Me too Bat.....I've been reading horror stories about ruined seals and rebuilt outdrives caused by fishing line.

It's still up in the air if we will be out this weekend.  Weather is sketchy.  Does Hidden Cove have fireworks on the 4th or do they do it later in the year?

[HALL'N]

Hey nlma1995,
Hope you're having a great weekend. We are at Litha Springs Marina,B dock usually hang around Skull Creek across from Point 2

[nlma1995]

Well good news and bad....We went out this weekend and the boat ran great for about the first 2 hours. (thats the good news)  We stopped had lunch, did some swimming and started to cruise home when my same problem came back.  We were running about 3800 RPM and about 30-32 MPH when the boat started to feel like it was dragging again.  I looked down and noticed that I was losing speed so I gave it a little more throttle to where I was up around 4400 RPM again just to maintain the 30-32 MPH range.  I powered down again to a stop and gunned it to check my hole shot and still have plenty of power.  I don't think it's a prop or engine coupler since I can put a great load on it and I don't feel any effects.  The motor seems fine...... Temp, Voltage, Oil pressure all good.

I guess the little bit of fishing line I found last week was not the culprit.  Is there anything else I should be searching for?  I'm back at a loss again.  I checked the drive oil to see if I was losing any or gaining water which I'm not.  Could something have happened to the gears?

If I were to take it to a marina, what do you think they would do for a test to try to duplicate the problem?

[bat32]

Fireworks are later, I can get you an exact date when I find out. 

As for the marina, they will go for a test drive with you if neccessary.  I have all my work done at Custom Marine in Seneca.  They have always done right by me. 

[atchuuu]

I had a similiar issue last year. I was running the boat for several hours when I started to lose power in my Starboard engine. For me the issue was plugs. I changed all the plugs and have not had any additional problems. I was suprised this did the trick as I only had 70 hours on the engines.

[NavyCTRC]

Does the engine sound different?  If there isn't a noticeable increase in noise due to the higher RPM indicated then I would suspect the tach first.