Trim Pump Vent Screw

Alumarine

Captain
Joined
Feb 22, 2005
Messages
3,684
Hi There. Just removed the Vent Screw on "my new to me" used trim pump and noticed that it looks like a #10 Sheet Metal Screw with a Blunt Nose.

Just wondering if that's the correct screw for the vent?
The fill screw is a machine thread.

Also, I need to replace the plastic down hose (lower circled fitting) that goes from the pump to the trim indicator piston. What kind of pressure is on this hose?

Thanks

pump2.jpg
 

wcsparky05

Petty Officer 1st Class
Joined
Feb 5, 2007
Messages
204
Re: Trim Pump Vent Screw

everyone knows sheet metal screws aren't meant for engines bit some idiot zipped it in there. personally, i would use a tri-tap and rethread the hole to, maybe the next size larger, but one that fit correctly. some may differ and say, if it doesn't leak, it's ok. you're call. about the trim hose, i can't help you there, but i'm sure someone here will, sooner or later. good luck!
 

Reel Poor

Vice Admiral
Joined
Jan 29, 2005
Messages
5,522
Re: Trim Pump Vent Screw

Pump pressure is 400 to 600 psi on down side, and 2200 to 2600 psi on the up side.
 

Alumarine

Captain
Joined
Feb 22, 2005
Messages
3,684
Re: Trim Pump Vent Screw

Thanks for the prompt replies.

Anyone know what size fastener should be in the vent hole?

Also, if it's a machine screw - how does it vent?
 

ziggy

Admiral
Joined
Jun 30, 2004
Messages
7,473
Re: Trim Pump Vent Screw

if yer gonna tap that hole. i'd be concered about where the metal shaveings from the tapping process go. like into the trim pump maybe. that might not be to good for it.....i think if it were mine, i'd just leave the sheet metal screw in it and leave well enough alone...it's just a vent......
 

crawdadric

Petty Officer 3rd Class
Joined
Nov 29, 2005
Messages
88
Re: Trim Pump Vent Screw

Marc C,
On http://dougrussell.com web site, I found the reservoir fill plug part number 392-7728 for $4.39 each. I looked under Mercruiser Alpha 1 "Hydraulic Pump Prestolite" parts listing.
Crawdadric
 

Alumarine

Captain
Joined
Feb 22, 2005
Messages
3,684
Re: Trim Pump Vent Screw

Marc C,
On http://dougrussell.com web site, I found the reservoir fill plug part number 392-7728 for $4.39 each. I looked under Mercruiser Alpha 1 "Hydraulic Pump Prestolite" parts listing.
Crawdadric

Thanks for the link. I found some part numbers for an older model that might help me out.
 
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