OMC Auxiliary Motor Bracket Air Spring source

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Trp34

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I have an OMC Auxiliary Motor Bracket with a dead lift cylinder (Air Spring). It looks a lot like a shock absorber but is actually a sealed air spring. It has a Schrader valve that I believe I can add compressed air, nitrogen or CO2 to, but I don't know what kind of pressure we are looking at. Would anyone have any experience with the device and be able to advise me on if this would work, if the spring is re-buildable, or where I can get a replacement? All parts sites list it as unavailable. Part in diagram is #35.

Thanks

Engine lift.png
 

oldboat1

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Never had one, but think I would try it with under 10lbs pressure and see if it functions. Spray with soap mix first to look for leaks. Assume you have tried Google searches?
 

Trp34

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I have searched, without any success on Google. I have a feeling the pressure is much higher. Design puts spring at a mechanical disadvantage and it has to lift an 85# motor through a parallelogram arrangement. I'm guessing there needs to be about 125-150# force at the spring. If it acts like a 1" bore air cylinder, it would need about 160-200psi. Good advice - I'll start low and work up from there. Sucks when products loose support. Guess I should stop using Windows XP and Netscape! :)
 

oldboat1

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...or my Betamax.

Can't believe that little cylinder would safely take 200psi. Maybe the spring itself is the primary assist. Would be interested in your findings/repairs.
 

boobie

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Where is this bracket listed in an OMC parts book ?? Year and ect ??
 

racerone

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Listed in the accessories from 1978 to at least the year 2000.-----Quality item and it was not cheap !
 

Scott Danforth

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if your seals are good, add about 200 psi of nitrogen.

many gas struts have well north of 2000 psi of nitrogen when collapsed
 

Trp34

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Thanks for the replies. The links to the part show a very high price, but are unavailable. I will experiment with different pressures with and eventually take it to a suspension shop for a nitrogen charge provided seals are good. Boat has been stored for a year and a half in the compressed position. the tiniest leak at a seal or Schrader Valve could empty it in that time. It doesn't bother me if it needs periodic refilling. To limit moisture, I can use a CO2 bicycle inflator once I know the right PSI.
Last resort will be to adapt a commercially available gas spring(s) from McMaster Carr or elsewhere.
 

Orang686

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Feb 8, 2022
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Any updates on this in same boat looking for replacement shock. Does any one have the closed and open length on the factory one?
 
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