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Problem engaging forward and reverse.

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pjt340

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Hi y'all, i have a 1973 24ft custom boat from south florida. The manufacturer is a mystery but thats a whole other issue. It has a volvo penta AQ250. When i bought it the boat had been stored indoors for the last 32 years. It does not want to go into gear when it should. Shifter and cable appears good and it is also appears to be activating the linkage properly. It actually engages the prop but when in the water under load the boat barely moves. After some waiting and revving it will engage. Reverse is the same but will engage with less wait than forward. Any ideas? Thx paul t.
 
Paul, the 250 drive uses the same basic cone clutch design as the 270 through the SP drives. The drive oil will be 30W engine oil.

I'd remove the eccentric piston housing and look inside to see if the shift shoe is in tact. If the shift shoe is functioning, the sliding sleeve should make contact with each gear cup.
The steep spiral splines are what cause the sliding sleeve to further engage once initial friction occurs.
Once engaged, they just don't let go.... usually!

Also look for any rust ar/around the gear cups, or for water or cantaminates in the oil.

Rick
 
Have you checked whether the prop is spun. I say that because you say even when in gear it hardly moves.

"It actually engages the prop but when in the water under load the boat barely moves."
 
No not spun. Will eventually klunk into gear. QUOTE=Mujibar;407352]Have you checked whether the prop is spun. I say that because you say even when in gear it hardly moves.

"It actually engages the prop but when in the water under load the boat barely moves."[/QUOTE]
 
Just to clarify, in post #2, Paul is quoting my response to a PM that he sent to me.

Paul, FYI... when you quote someone, highlite their text, and then click on the "Wrap
tags around selected text"
Click to expand...
icon above.
(you must be in Edit or Go Advanced mode in order to do this)
Make sure that the brackets do not become corrupt. I.E., [ QUOTE ] >quoted text here< [ /QUOTE ] (spaces removed).
If one space, one character or a bracket is off, it won't show up as a quote. ;)

Make the "quote" first, and then your response afterwards.... easier to read that way!:D


As said earlier.........
RicardoMarine via a PM said:
I'd remove the eccentric piston housing and look inside to see if the shift shoe is in tact. If the shift shoe is functioning, the sliding sleeve should make contact with each gear cup.
The steep spiral splines are what cause the sliding sleeve to further engage once initial friction occurs.
Once engaged, they just don't let go.... usually!

Also look for any rust ar/around the gear cups, or for water or cantaminates in the oil.
Rick
Click to expand...
Click to expand...
 
Last edited:
In response to post #2:
Rick, I had asked whether I should be using straight 30w in the outdrive as I am using penngrade 10w30. I'm not sure if I mentioned this but the prop does turn when engaged in F and R . but it must be barely engaged because when encountering the resistance in the water it hardly moves the boat.
Also, I am not familiar with those parts you mentioned. You mentioned you had some photos to help clarify. That would be greatly appreciated.
I do have access to a exploded view of the parts from the repair manual. thank you
 
Paul, find your engine via the AQ number that references engine model, not the drive model.
Example: AQ260/280 ... the 260 would be the engine, the 280 would be the drive.

See this web site..... it will list all AQ series engines.


.
 
Paul, being that this is the Holman Moody set up, the H/M components pertain to the adaptataion only.
Holman Moody takes the engine to the Volvo Penta drive via a Borg Warner pattern flywheel cover and a Borg Warner pattern PDS adapter housing. The web site that I linked you to won't do you any good, unless you are very familiar with the older AQ series drives!


The AQ250B would tell me that the drive is a 250..... and the "B" designation says 1.61:1 over-all gear ratio.
The "B" is good only if the lower unit has not been swapped out for another ratio.

None-the-less, your gear oil will be 30W. The Multi-viscosity should not hurt anything.
However......, some "synthetic" oils prevent the brass sliding sleeve from achieving enough friction to lock up and fully engage!
The fix is complete disassembly of the transmission, and then gently lapping the brass sliding sleeve into each driven gear "cup"!

There is no OEM procedure for this....., so you're on your own if you were to do this.
I can't tell you how many times that I've done this myself (23 years or so of AQ series repair), but will tell you that it works just fine!
There are several tricks to this, if interested.



.
 
I had a 10hp diesel in my sailboat. It had a cone clutch which got hard to engage...once it was in it was OK, but often took several tries. It came from the factory with gear oil. I lapped the cones and put in straight 30 and never again had the problem. There was a service bulletin to quit using gear oil, but it didn't get to me until well after I'd done the work.
 
pjt340 said:
What is lapping the cones?
Click to expand...
Valve Lapping compound used to de-glaze the conical sliding sleeve face to the corresponding gear cup.
You will not find any OEM procedure for this.
However, I will suggest that there is a more correct procedure, but it would involve a few images, and perhaps a phone call.

Upper sliding sleeve face to upper driven gear cup, and visa-versa.
Even rotation, rotating both gear cup and sliding sleeve simultaneously as to apply equal pressure.

A good machinist would know how to perform this, even if he had never seen a Volvo Penta drive before.


.
 
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