jet POP OFF Valve on Ebay (spam)

[wsm9808]

Thought maybe someone on here might be interested in a Pop off valve.
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=4583467150&rd=1&sspagename=STRK%3AMESE%3AIT&rd=1

[ONAROLL]

Same one I have on my Mantra Tunnel now, still dont know who made/modified it, but mine works perfect, I quickly got outbid but I'll keep em honest......Vic

[olbiezer]

just what does a pop off valve do anyway......( my boat has a prop ) lol

[BUSBY]

This pop off is a Melleur (sp? ... sounds like mell-oor) valve. They worked pretty well. Almost like a Nelson housing. Tom Papp knows them well ... I'm thinking no more than $350-$400.
Ol' ... pop off's allow the intake pressure to bypass the impeller by releasing the volume out of the hand hole access in the suction piece. It requires a pump set back or modification of the transom. Usually there is no need unless you are racing and in speeds exceeding 100 mph. They will let you slow the boat without "stuffing" the nose when you let out of the throttle.
A jet does not have dogs in a whirl-a-way or anything like that unless you buy a ratchet, so when the boat is at full speed, the intake is still charging. Since a jet is a direct drive, when you take your foot out of the throttle, the impeller stops turning back down to idle (or whatever speed the engine is turning) since the intake for the pump is still taking full speed volume and not able to exhaust it ... the tail kicks up due to an overload of the pump, therefore "stuffing" the nose. Not good at speed.
that's what a pop off does ... bascially ... hope that makes sense ...
Brian

[olbiezer]

thanks......so if u had a rachet u dont need a pop off? thanks again..

[BUSBY]

thanks......so if u had a rachet u dont need a pop off? thanks again..
Well ... no, not in my opinion ... I think if you're running a jet faster than 100 ... you'd need both. Reason being, they do to different things ...
A ratchet will allow a pump to free-wheel when there is a motor failure ... it has dogs similar to a whirl-a-way in it ... if the motor locks up, the pump will still turn and release some of the pressure in the intake ...
A pop off will blow in case of an intake over-pressure or manual release (driver chooses to blow it off) ...
So, IMO, in a perfect situation, you would have both ... a ratchet and a pop off. A ratchet in case of a motor failure/lock up & a pop off in case of an intake pressure that is too high or when the driver wants to safely slow the boat down ...
I hope that made sense ...
Brian