Need Help ASAP! Boat wont move past about 10mph

[Chris Hyde]

1992 Wellcraft 186 with Volvo 4.3 and Volvo DP outdrive.

I put the boat into the lake today for an afternoon tubing run. I only had 3 people in the boat. I backed it off the trailer, cruised over to the dock to pick up the 2 passengers, turned around and headed out to the main body. As soon as I gave throttle, the boat started to stand up like it normally does, but then the RPM's would increase, but the boat would not got any faster than about 10mph and would never plane.

Relaying this scenario to an automobile, it was like the clutch was slipping and not going any faster than about 10mph. Of course I am not aware of a clutch in this case.

So, I put it back on the trailer and go through a quick dry run of the throttle in forward and reverse on the launch ramp. Prop spins fine, no noises so I put it back in the water with no passengers. Same thing. I cant figure out what could be going on. Anyone have opinions?

PS, I pulled the top dipstick out of the outdrive and the oil was kinda greyish, smelled bad, but the complete dipstick was covered from one end to the other. The boat has been perfect for the last 4 weekends, so I am not sure here.

HELP!

 

[maxumized]

Re: Need Help ASAP! Boat wont move past about 10mph

I'll take a shot at this...

If the rpms are moving but the boat isn't, it sounds like either prop hub or coupler hub could be spun.

 

[Chris Hyde]

Re: Need Help ASAP! Boat wont move past about 10mph

The props spin as they should by hand and also on a quick dry run on the ramp. How do I diagnose your suspicions?

 

[chiefalen]

Re: Need Help ASAP! Boat wont move past about 10mph

Do you have a spare prop? Could be a spun prop where the rubber core is letting the metal blades to spin.

Try a different prop. I hope its that.

Cause the next thing i would suspect is the coupler thats big money to change out. Engine has to come out.

 

[danond]

Re: Need Help ASAP! Boat wont move past about 10mph

My "big money" mark is anything over $1000. A coupler should come in under that.

Put the drive in gear with the engine off and try to turn the prop. It shouldn't turn (obviously). If it does, note whether you're turning the prop and hub. If you are, your coupler is probably busted. If not, get your prop to a prop shop for a rebuild.

 

[Chris Hyde]

Re: Need Help ASAP! Boat wont move past about 10mph

Ok, the inside prop spins if I turn is hard enough by hand while holding the first prop. I took the props off and this is what I found. I think we have a blown rubber bushing and it appears to have been this way for a while and has eaten up some of the metal on the snout of the bearing housing.

The inside prop (side 1):

The inside prop (side 2):

 

[chiefalen]

Re: Need Help ASAP! Boat wont move past about 10mph

Did you maybe hit something. You got away lucky.I always keep a spare prop on my boat.

 

[Chris Hyde]

Re: Need Help ASAP! Boat wont move past about 10mph

Did you maybe hit something. You got away lucky.I always keep a spare prop on my boat.

I havent hit anything. I think it just finally gave out. So a new rear prop should do the trick? My next question is this.

What keeps the new prop from going back far enough to rest on that metal snout and continue eating? Is there "stop" where the new prop is supposed to stop?

 

[sea wolf]

Re: Need Help ASAP! Boat wont move past about 10mph

What the he** happened to the lower unit? I'm not too familiar with Volvos, but isn't there supposed to be a bushing on the prop shaft which goes on first, then the prop itself? I could be wrong but it looks to me as if the prop has been spinning flush against the lower unit & has chewed the sh** out of it. Yea, the prop is a goner.

 

[Chris Hyde]

Re: Need Help ASAP! Boat wont move past about 10mph

What the he** happened to the lower unit? I'm not too familiar with Volvos, but isn't there supposed to be a bushing on the prop shaft which goes on first, then the prop itself?

Thats what I am asking. I'd love to see an axploded view, but I am not sure which model Volvo outdrive this is because it only says CD Trim on it.

 

[sea wolf]

Re: Need Help ASAP! Boat wont move past about 10mph

Well, I think you ran the boat without the bushing, which has caused the damage. The prop is spinning against the lower unit. Gonna cost you.

 

[Hitech]

Re: Need Help ASAP! Boat wont move past about 10mph

I don't know much about that stern drive, but the round collar part that is all "chewed up" is a zinc anode.

 

[Chris Hyde]

Re: Need Help ASAP! Boat wont move past about 10mph

I don't know much about that stern drive, but the round collar part that is all "chewed up" is a zinc anode.

Actually, I pulled the ZINC anode off before taking the pic.

 

[Maclin]

Re: Need Help ASAP! Boat wont move past about 10mph

No bushing first, but there should probably be a fish line cutter that goes on first, fits butt up against the shoulder on the shaft and back over the housing. The cutter is very thin. The front prop's hub butts up against that. The prop itself extends into the anode some.

The damage shown could have been done by improper installation, or maybe just a bad hub and the prop wobbled around and went toward the front of the shaft where it was not supposed to be.

Here is a link to a thread that describes what I went thru to get my first set of DuoProps back on correctly after a Marine dealer removed them "for me"...

http://forums.iboats.com/showpost.php?p=1340986&postcount=5

It is also a good idea to clock the props when installing. Here is a link that describes what that means and why it could be important...:

http://forums.iboats.com/showpost.php?p=1729834&postcount=1

 

[Maclin]

Re: Need Help ASAP! Boat wont move past about 10mph

You probably have a 290DP, that is what mine says on it (CD TRIM). The 280DP and 290DP prop stuff is the same. The first link in my post also has a link in it that shows the parts explosion.

 

[Maclin]

Re: Need Help ASAP! Boat wont move past about 10mph

The anode is still on the drive in your first pic....

 

[Don S]

Re: Need Help ASAP! Boat wont move past about 10mph

Looks like the line cutter/spacers were left out between the prop and drive. This lets the prop hub rub on the housing and they both wear away.
You need to find a VP dealer that can replace the seal housing and reshim the lower into a new housing. You don't have the special tools to do the job.

 

[Chris Hyde]

Re: Need Help ASAP! Boat wont move past about 10mph

You probably have a 290DP, that is what mine says on it (CD TRIM). The 280DP and 290DP prop stuff is the same. The first link in my post also has a link in it that shows the parts explosion.

Do you think the bearing housing needs to be replaced or should I be good with a new fish line cutter and new front prop?

Edit: Don, I didnt see your reply before I posted this post.

 

[Don S]

Re: Need Help ASAP! Boat wont move past about 10mph

Edit: Don, I didnt see your reply before I posted this post.

Now you do, bet you wish I didn't answer.

 

[Chris Hyde]

Re: Need Help ASAP! Boat wont move past about 10mph

Could I not simply replace part #3 (bearing housing) in this diagram since that is the only part that seems to be chewed up a bit on the snout end? Then replace the plastic washers, front prop and line cutters and be back operable?

When I set the old prop back on, it still doesnt rub the bearing housing. I think all the metal chewing came from the inside bushing of the prop being destroyed which resulted in letting the prop hosing chew up the metal a bit.

http://www.volvopentastore.com/LOWE...egory_id.333062--store_id.366--view_id.326591