290 DP shift problem-gctid392933

[Guest]

I have 2 new-to-me 280 DP legs on my 3250.

One of them seems tough to find neutral - shifts fine into fwd and reverse. The 'band' for neutral is narrow and I often go right past it and into the other gear. Makes things a little 'exciting' when docking and has provided some entertainment for the docking judges . Juggling the shifter to try and find it seems to help - or maybe that is my imagination! The other leg is fine.

The idle is ~ 600 / 700 rpm, so I don't expect that is the problem. Oil is new. I don't think it is a cable issue.

Any thoughts on what order to check things to diagnose the issue?

Thanks in advance!

(P.S. performance and fuel consumption figures comparing SP to DP are on the way)

[2850Bounty]

nmuir wrote:

• 1 wrote:
• I have 2 new-to-me 280 DP legs on my 3250.
• One of them is very tough to find neutral - shifts fine into fwd and reverse. The 'band' for neutral is so narrow that I typically end up going right past it and into the other gear. Makes things a little 'exciting' when docking and has provided some entertainment for the docking judges . Juggling the shifter to try and find it seems to help - or maybe that is my imagination! The other leg is fine.
• The idle is ~ 600 / 700 rpm, so I don't expect that is the problem. Oil is new. I don't think it is a cable issue.
• Any thoughts on what order to check things to diagnose the issue?
• (P.S. performance and fuel consumption figures comparing SP to DP are on the way)

I'll preface this by saying that it is odd to see a cone clutch drive want to pass through neutral and go right on into the next gear engagement.

Typically, the shift shoe and sliding sleeve geometry and spacing does not give us this type of shifting issues.

There are three distint eccentric piston detents that hold positions.

In the first image below, look at pin #4. This is the eccentric piston detent pin.

What you cannot see, is the adjacent detent grooves that this pin rests within during all three selections.

What this means to me, is that this may be within the cable or shift unit itself.... and perhaps not in the drive.

The only Caveat to this might possibly be glazed cups from the bronze material of the sliding sleeve, in which case careful lapping of the sleeve to cups may be in order.

There is NO Volvo Penta procedure spelled out for this. If you were to do this, contact me.

None-the-less, here's what I'll suggest to you:

• 1 wrote:
• As in "recently installed" and recently attached shift cables, etc?
• Since we are not fighting dog teeth friction and resistance with cone clutch type gear engagement, these generally move In/Out of each position very easily. In fact, I'm rather surprised to hear that your one transmission is doing this.
  
  Below is a schematic of an early 290 transmission.
• The RPM range seems to be OK.
  
  Higher RPM causes more engagement into the gear cups since the cone clutch system relys on torque for sleeve/cup engagement.
  
  Contaminated gear oil can cause issues, however this usually causes slipping, not a disengaging problem.
• The boat needs to come out of the water in order to fully check things out.
  
  Disconnect the shift cable from the gear yoke https://"http://www.marinepartseurop...is schematic).
  
  While looking at that schematic, note SEQ #33. This bracket must be secure and must be catching the slot in the shift cable housing.
  
  (and while un-related, make sure that you replaced SEQ #'s 28 & 29 on both drives!)
  
  See if the eccentric piston moves freely.
  
  If it does, then you may have an issue with a bad shift cable or shift cable attachment point somewhere.
  
  If not, disconnect the vertical linkage piece, and again see if the eccentric piston moves freely.
  
  If it does, then you may have an issue with the https://"http://www.volvopentastore....or lock brace. This primarily affects REV!
  
  Also, with the oil drained, remove the shift mechanism from the main gear case. See if the shift shoe is damaged.
  
  Look for any signs of water damage.
  
  This will cost you 3 new O-rings and a fill plug gasket when going back together.
  
  
• That would be good.
  
  I wish that I'd had taken some stats when I went from single prop drives to the Duo Prop drives.

Here is a 290 transmission. Parts are similar, if not same, for your 280 transmissions.



I hope that you are able to get this sorted out!

In the BOC Vault, there is a https://"http://www.baylinerownerscl... <br /> thread regarding Q's and A's for the AQ series Volvo Penta engines/drives.

Or just click on the link beneath my signature.

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