new boater, outdrive issues

Just bought my first boat. 2004 sea ray 180 sport with 3.0 mercruiser alpha one with 150 hours at purchase. Out on the lake today for the second time, put 4 hours on it since we bought it. after an hour on the lake I was pulling the boat up onto a plane and out of nowhere the rpms shot sky high. I immediately backed off and checked the bilge, but everything looked good and engine was running good. I then tried to get it back up on a plane, but you could just feel at some point the rpm were going WAY higher then it should be for the speed I was going. I assumed the prop was slipping on the shaft and just limped it home. Once the boat was on the trailer I peeked at the prop expecting to see a sheared off pin or somehting but everything actually look good (of course i dont really have any idea what im looking at). So now im fearing that 4 hours into my first experience with a boat the outdrive has let go. Any one have any idea what this could be?

Re: new boater, outdrive issues

Sounds like your hub is slipping. Take a scribe, or grease marker and make a line from the center of the prop shaft to prop, then run it wot and bring it back in and see if the lines still line up.

you can get a new hub from any decent boat shop/

Re: new boater, outdrive issues

+1 Spun hub.

Re: new boater, outdrive issues

Agreed ^^^
There is a slim chance its the coupler But most likely the prop hub.

Re: new boater, outdrive issues

It'd be nice if it was just a prop hub.

On any used boat purchase, I always recommend the following be done immediately upon purchase:
1. Repack the hubs on your trailer.
2. Drain and replace the lower unit grease--looking for any water contamination.
3. Have a qualified mechanic do a pressure and vacuum test on the lower unit to make sure the seals are good. ($300 repair if not.)

You don't want any surprises out of your boat, and the above maintenance items can sometimes simplify your life.

Re: new boater, outdrive issues

I belive you are looking at a spun prop hub or bad coupler as I don't believe it is possible for an alpha to slip the gears are in or not.

Re: new boater, outdrive issues

With the engine shut off, put the drive in forward. Try to spin the prop counterclockwise (when viewed from the rear). If you can turn it there's a problem....maybe a spun hub, although this isn't very likely unless you've hit something which would have probably left marks on the prop. If you had real drive problems you'd hear some nasty noises out back so hopefully it's a simple problem....or nothing....

Not trimming the drive all the way in (down) can also make this happen; are you sure you didn't have the drive trimmed out? I bring this up only because you're new to the sport; we've all done this at some point in time so don't feel bad if this is the case.

Re: new boater, outdrive issues

I still think spun hub. Especially if its pressed in. The SS prop on my pontoon was spun and didn't have a mark on the blades. And yes, if you hit something with a SS enough to spin the hub it will leave a mark. I had the same symptoms. Anything above 3500 resulted in more revs with no change in speed. Marked it and sure enough it was spun.

Re: new boater, outdrive issues

No pins to break... As others have mentioned there is a rubber hub that is pressed tightly into the center of the prop, with splines in the middle of the hub that contact the prop shaft on the drive. If this hub has loosened up, either by an impact or some other means, you will experience what you are experiencing right now.

Is there a chance the previous owner had the prop gussied up before he sold the boat to you? I see an occasional post here about someone who has just gotten their prop back from a prop shop, and have a spinning issue with the new hub the shop installed.

Re: new boater, outdrive issues

Im positive the trim was all the way down, and im positive I didnt strike anything with the prop. No funny sounds from the outdrive. I can set it at low throttle and it will put along fine. Its just when i go to gas it, at some point it just lets go and rpm's shoot way up. No other sounds along with that. Im going to take it in to have it looked at soon and I will let you guys know the outcome. I may go up a touch on the pitch. Prior to this happening at WOT it was running at just shy of 5k rpms, and that from what I have been reading is to high for the merc 3.0. Would it be a mistake to do this? Could that have also have been a result of some slipping and just not realizing it?

Re: new boater, outdrive issues

Don't waste your money taking it in. The hub is slipping, that's why you get to a certain point and your rpm's shot up, and your WOT is high. Pull the prop off and get another prop the same size and pitch. get it from here for 100 bucks.

Re: new boater, outdrive issues

amadio1 said:

Prior to this happening at WOT it was running at just shy of 5k rpms, and that from what I have been reading is to high for the merc 3.0. Would it be a mistake to do this? Could that have also have been a result of some slipping and just not realizing it?

Click to expand...

Remember, you're running in cool temps now. In hot weather (and with more of a load) your rpm's will decrease. Also, the tach on the dash may or may not be accurate....probably isn't. I wouldn't do anything with the prop just yet.

Always a good idea to have a pro take a look at it and run it if possible. Much as we try, it's damn near impossible to diagnose most problems over the internet. It could be prop slip; most boats are a little prone to that as the bow starts to come down when you're coming on plane, especially if you leave the stick pinned to the firewall. Then again it could be a "spun" prop hub (as many have opined)....your mechanic will let you know.

Re: new boater, outdrive issues

So, the next question. Is there any real reason to spend the extra money for a stainless prop? Im not all that into performance at the moment, and its just a 3.0 merc. The intention for the boat is for day trips 1-2 times a month for lazy cruising, fishing, and the occasional pulling my daughter around on the tube. Im fully aware of the benefits of SS material over alum, im a machinist by trade. But as a first time boater, and for my purposes, is it really worth while to spend the extra money?

Re: new boater, outdrive issues

amadio1 said:

So, the next question. Is there any real reason to spend the extra money for a stainless prop? Im not all that into performance at the moment, and its just a 3.0 merc. The intention for the boat is for day trips 1-2 times a month for lazy cruising, fishing, and the occasional pulling my daughter around on the tube. Im fully aware of the benefits of SS material over alum, im a machinist by trade. But as a first time boater, and for my purposes, is it really worth while to spend the extra money?

Click to expand...

For your purposes, no need to switch to stainless. An aluminum wheel will work just fine, and Iboats usually has good deals on them.

Re: new boater, outdrive issues

After making the switch to SS many years ago I'm a big fan of them. The performance differences go way beyond speed although you're not likely to save enough gas to pay for the difference in price. I'd say no it wasn't worth it, unless you happen to run across one at a prop shop (or on ebay) that's a smokin' hot deal. For $100-$150 I'd make the switch, but probably not if you're paying $300+ for a new one. A spare prop however is a good idea. I've always liked to have a "speed prop" and a "power prop", depending on the particular use and conditions of the day. Swapping props is an easy, 2 minute procedure, and there's no such thing as a swiss army prop.

Honestly, as a new boater, it appears you're doing the right things; i.e. asking good questions on forums, building a relationship with your mechanic and hopefully keeping up with the maintenance on your pride and joy. IMO you made a great choice in a first boat; I wish mine had been so nice! My advice is to continue to do that unless/until you find that your current boat no longer meets your needs and wants or you or your family gets bored with boating. Far too many people get "three-foot-itis" or "upgrade-itis" and wind up throwing so much money at the hobby that it's no longer fun for them and they wind up dropping out. That's a real shame; boating is a great hobby/sport but like many things it can get addictive. Maintain your self discipline, have fun with it and try to keep it as stress free as possible through good maintenance procedures. There's lots of super gee whiz bang things out there to buy (props being one of them), but almost none of them will make you have more fun on the water.

Re: new boater, outdrive issues

I thought it was a good buy at 7 grand. 2004 Sea Ray 180 sport. 150 hours. Wanted to start small, and after a year or two of learning upgrade to the 21ft regal ive been drooling over.

Re: new boater, outdrive issues

Sounds like a good buy (so long as it's in good running order) but as you're starting to figure out, the cost of ownership goes WAY beyond the purchase price.

Hang onto it for a year or two; you may find you want something different, or you may find that the open bow layout perfectly suits your needs/wants. I can tell you that over the years what I wanted in a boat changed a few times.....and may change again depending on where and how I intend to boat.

Re: new boater, outdrive issues

UPDATE:

I've noticed that when someone posts about a boat issue, and gets many good opinions from the people here, that often they don't report back with their findings and how the issue was resolved in the end. So, I wanted to write in with good news that the problem was solved. I switched out the old prop with a new one. I went with a 3 blade alum 14.25 x 21. That fixed it. It was obviously a spun hub. The old prop will now go into the shop for reconditioning and have a new hub installed. All said and done it was a $180 fix. I decided to go with the alum prop over the SS due to the fact that im only running a 3.0L and we use mainly for cruising and fishing, and possibly light tube towing. I didn't feel the slight performance gain of the SS was worth the extra money in my case.

Next on the list for me will be tracking down the culprit of the rough idle and hard starting. Will have to check all the filters and maybe a carb rebuild. I suspect that it might be fuel related.

Re: new boater, outdrive issues

RogersJetboat454 said:

No pins to break... As others have mentioned there is a rubber hub that is pressed tightly into the center of the prop, with splines in the middle of the hub that contact the prop shaft on the drive.

Click to expand...

Depends on the prop. If it is a merc prop then that description is incorrect. The flo-torque hubs are basically a square piece of plastic that will deform and allow the prop to slip. Easy enough to just take the prop off and inspect the hub.

Re: new boater, outdrive issues

im with old jeep u have enough pros on here to help u forget payn a mech.. 300 or more to fix simply take it off n see how it looks if its scraped nasty lookn try a new hub or prop all together like they said only 100 bucks on here order one switch iot out n try it ...i bet it works !!!! ayyyhuh u did it alread there ya gooo... if the carb is just putting a lil u can try some seafoam run it through at least for know to get u some use it helped mine and lasted all year last yr and started right up this year its 10 busk a can add it to gas and spray it in carb follow directions it cant hurt just dont do too much spray at once ....ultimatley u will have to rebuild carbs but this may work for a lil longer or sooo who knows if its just hesitating a lil bit !!!