Anybody have a 205 Osprey with 200 HP Yamaha OX66?

[CLM65]

I've been trying to track down a loss of top end on my 2002 205 Osprey.  I had the motor, a 2002 200 hp Yamaha OX66, rebuilt a couple of years ago after I had a water-in-the-oil incident.  Ever since then, I haven't been able to achieve the same performance.  I used to be able to get about 48 mph, but I don't recall what the max RPMs were - I'm guessing about 5400-5500.  After the rebuild, I got about 4500 rpm max.  I went through all of the following (at least once):

cleaned VST filter
cleaned regulator filter
replaced all other fuel filters
replaced LP pumps
cleaned injectors/replaced injector baskets
checked spark plug cap resistance
changed plugs
compression check
link-n-sync
checked TPS voltage
cleaned O2 sensor (and tested with another O2 sensor)
decarb
probably one of two more things that I've forgotten

I now get 5000 rpm, with a top speed of just under 44 mph.  The engine runs very good, but I'm afraid I might be doing some long-term damage if something is preventing it from reaching full rpms.

So, if anyone else has this boat/motor combo, can you tell me what prop you are running and your top speed and rpm?  And does anyone have any other suggestions?

Thanks!

[flounderpounder225]

assuming you are running the same prop?  have you changed the boat in any way?  Bottom paint, T-top.. anything that would create drag?  are your throttle plates opening all the way open, is your throttle arm all the way to the stop at WOT?

[CLM65]

The boat hasn't been changed - always had a T-Top, no bottom paint, etc.  It is the same prop too, at least as far as I know.  I have no reason to assume this, but IF something happened to my prop (i.e., was stolen) while it was at the mechanic's shop for the rebuild, and he put one on that he had laying around out of the goodness of his heart, then maybe it is a little different.  Again, I have no reason to believe this happened, and it is highly unlikely, but if I can confirm that my prop is similar to what others have with the same boat/motor combo, then I can cross this off the list of possibilities.  There just seems to have been a step change at the time of the rebuild.

I did a link-n-sync, but I haven't specifically looked at the throttle plates or throttle arm at WOT.  Good suggestion!  Thanks!

[seabob4]

Craig,
If they are the original cables, it may b time for replacements.  Move the throttle to WOT, mark on the engine block where the throttle linkage is, then disconnect the throttle cable and move the linkage by hand, see where it ends up in relation to the mark...

[CLM65]

Thanks Bob, that's what I'll do.  Sure would be nice if it's the cables!

[CLM65]

OK, I finally got to check the throttle arm movement.  With the throttle cable connected and at WOT position, the throttle plates were fully closed.  When I discnnected the cable, I was able to move the throttle arm a bit more, although the throttle plates were already fully closed and didn't move.  As far as I can tell, that additional movement of the throttle arm did not result in anything else moving at all.

Here is a picture with the throttle cable connected (WOT position).



And here is one with the throttle cable disconnected and the throttle arm as far as it will go.



Is this normal?

[icemanbryan]

It was a female brain Abby something
 

[CLM65]

It was a female brain Abby something
 

Ummm....you lost me there, Bryan  

[seabob4]

It was a female brain Abby something
 

Ummm....you lost me there, Bryan  

LOL!!!  Young Frankenstien.  Abnormal...Abbie Normal...Remember?  Marty Feldman?

Craig, adjust your cable so that at WOT the roller is in the same position as the second pick.  Even though it appears noting else moved, if the motor has a TPS (throttle position sensor), then it would be delivering fuel based on position.  Give it a try...

[icemanbryan]

It was a female brain Abby something
 

Ummm....you lost me there, Bryan  

LOL!!!  Young Frankenstien.  Abnormal...Abbie Normal...Remember?  Marty Feldman?

Craig, adjust your cable so that at WOT the roller is in the same position as the second pick.  Even though it appears noting else moved, if the motor has a TPS (throttle position sensor), then it would be delivering fuel based on position.  Give it a try...

[gran398]

It was a female brain Abby something
 

Ummm....you lost me there, Bryan  

CLM, John Dupree is our resident expert on the Yamaha OX-66.

Will ask John to input here.

Thanks.

[CLM65]

Ha!  You guys crack me up!  I thought Bryan posted on the wrong thread!

Anyway, I will see if I can adjust the cable that much.  I think the post where the throttle cable connects moved about an inch or so.  Question:  won't that screw up the position of the throttle arm for idle?  Or is there a way of adjusting it at the helm to get a larger range of motion?

And if you answer with a line from a movie, you may have to include an explanation, because I can never seem to remember the really good movie lines !

[seabob4]

Craig,
On Yamahas, this is how I "adjust" the throttle and shift cables.  

Each end of each cable has an identical adapter on it.  Starting at the binnacle, I thread the adapters on so that the end of the cable is basically flush with the entrance into the hollow area of the adapter (the center portion).  I have found this gives me a healthy amount of leeway when the engine ends need adjusting, in or out.

Once that's done, then it is simply a matter of threading on the engine end adapters until the mounting holes line up with the studs on the throttle arm and the shift slide with the cables in their retainers.

In theory, and on new installs, a fraction of an inch of movement at one end will result in the same fraction of an inch movement at the other end.  The problem is this.  Over time and usage, cables become, for lack of a better term, "stretched".  Now we have a situation where that fraction of an inch movement at the binnacle end, for instance, produces NO movement at the engine end.  You have to go a little bit further to achieve the same action on the cable as before.  This problem manifests itself in reduced throttle throw (not seeing the WOT RPM you used to), a slightly higher idle RPM, and difficulty getting the motor into neutral (have to play with the lever a bit).

Now I'm not saying that this is the explanation for your loss of WOT RPM and speed.  But it sure wouldn't hurt to throw in a new pair of Teleflex XTreme cables.  I get all my cables of boatersland.com, excellent prices and service.  Assuming you'd need 20 footers, you're looking at about $80 for the pair...http://www.boatersland.com/tel-cc63320.html

[icemanbryan]

It was a female brain Abby something
 

Ummm....you lost me there, Bryan  

CLM, John Dupree is our resident expert on the Yamaha OX-66.

Will ask John to input here.

Thanks.

My money was on Bob to get it!

[seabob4]

My money was on Bob to get it!