Quantcast

Anti-Siphon Valves

Classic Parker

Help Support Classic Parker:

TomS

Administrator
Moderator
Joined
Feb 17, 2006
Messages
702
Reaction score
0
Location
Newburyport, MA
I had a hard time changing the filter on my fuel/water seperator last fall because of all the gasoline that drained out when I removed the filter. I expected there to be a little spillage from both the motor and tank sides, but it just kept coming. At about the 1 gallon mark I got nervous and decided to abort and button everything back up. I caught most of the gas in a bucket (thought ahead for once) and managed to clean out the rest before winterizing the boat.

After doing some research and asking around, most people do not have this problem because they have an anti-siphon valve inline somewhere from their fuel tank, usually where the fuel line is attached to the tank.

I PM'd Alan (hunt4fish) who has the exact same year/model/engine as I did, and he did not have this problem.

So I surmised that my boat did not have an anti-siphon valve installed, or that it had become inoperable. I went out after lunch to take a look, and after a bit of work, I do not have an anti-siphon valve installed (at the tank anyways)

So... could it be anywhere else? This wouldn't make sense because you want it as close to the tank as possible, correct?

Any reason not to install one, now that I've pulled it out?

What kind of sealant should I use to put everything back together? I noticed that there was something on the threads, and also at the base of the hose where it went over the barbs.

-- Tom
 

Attachments

TomS

Administrator
Moderator
Joined
Feb 17, 2006
Messages
702
Reaction score
0
Location
Newburyport, MA
FYI,

Just got off the phone with an engineer at Parker. He confirmed that the only place there would be an anti-siphon valve is right at the fuel tank fitting. He also said that they are now standard on all Parkers leaving the factory.

-- Tom
 

DaleH

FOUNDER of Classic Parker Forum
Moderator
Joined
Feb 16, 2006
Messages
4,651
Reaction score
15
Location
Newbury, MA
TomS":c0r72jhu said:
I do not have an anti-siphon valve installed (at the tank anyways).
It could be that you do, or you did ... but someone removed the "guts", which is a stainless steel spring and ball. A new anti-siphon valve would look just like the piece in your pictures, but would be complete. My Parker had the same issue as yours, and it looked to be a AS fitting, but the AS guts weren't installed or were removed. I once was told that the AS fitting and the regular barbed fitting come off the same production line when manufactured, with the AS fitting getting the ball & spring installed and the std fitting without. Makes sense.

FYI the compression rate of the spring and weight of the ball are enough to stop any unintended flow from the tank without the draw of the vacuum from the OB's fuel pump to pull it through. Yet not so stong as to be an added fuel restriction within your fuel system.

TomS":c0r72jhu said:
Any reason not to install one, now that I've pulled it out?
Not that I can envision, specially if your fuel line takes a dip below the tank level at any place. OB boats aren't as prone to siphon problems as are other boats, from a safety standpoint, as your source of ignition is outside the bilge area. But a good AS valve will not hurt your system.

TomS":c0r72jhu said:
What kind of sealant should I use to put everything back together?
I have some fuel-rated Permatex you could borrow. I have used teflon tape in the past, but you need to be very careful with the install with this method, as you must wrap it in the direction the female threads will bear onto the tape (not against that twisting motion) and you must keep the tape away from the first few threads. Allegedly t-tape can also "creep" over the years, though I've never seen it happen. I just use the PTex now that I bought a container of the good stuff.
 

TomS

Administrator
Moderator
Joined
Feb 17, 2006
Messages
702
Reaction score
0
Location
Newburyport, MA
Thanks Dale.. I just checked the sealant that I had.. Permatex "Thread Sealant with Teflon" which is rated for just about everything but fuel -- figures..

Will pick some up at an auto-parts store, as I want to turn this around fast, nothing is hooked up right now.

-- Tom
 

DaleH

FOUNDER of Classic Parker Forum
Moderator
Joined
Feb 16, 2006
Messages
4,651
Reaction score
15
Location
Newbury, MA
Good fuel-rated Permatex is $8-12 for a lifetime supply ... I can get my can to you on Thursday or you can pick it up from my house tomorrow morning.
 

TomS

Administrator
Moderator
Joined
Feb 17, 2006
Messages
702
Reaction score
0
Location
Newburyport, MA
Thanks Dale, I picked up some on the way to West-we don't have it in stock, but the BOATUS up the street might - Marine.

Come to find out that Anti-siphon valves with 3/8" NPT threads and 3/8" hose barbs aren't too common.. ARGH.

-- Tom
 

dougmacf

Active member
Joined
Feb 24, 2006
Messages
36
Reaction score
0
Location
Marshfield, MA
FWIW, my '93 225 OMC has a VRO system whereby oil is metered into the "clean" fuel stream from the tank just before entering the engine.

According to my mechanic, my '89 Parker doesn't seem to have an anti siphon valve in the fuel line. When the engine is shut off, some of the "oiled" fuel siphons back down the line toward the tank.

When I start it up next time, a small but significant amount of fuel is "double oiled" resulting in rough startup and a lot of smoke. No harm done; better more oil than no oil, but it's annoying. It's especially noticeable when I only run the engine 15-20 min. and back to the dock for some reason.

I asked about adding an anti siphon valve inline ( as well as a Flowscan fuel metering device) and his answer was the same for both; that the engine is very sensitive to any fuel restrictions (of unknown amount) and he'd be leery of adding one let alone 2 variables into an engine which really does run great as is (startup smoke aside).

Having a curious and scientific mind, I still think it would be a good experiment to try; I just won't bring it up when he de-winterizes the engine this month...
 

DaleH

FOUNDER of Classic Parker Forum
Moderator
Joined
Feb 16, 2006
Messages
4,651
Reaction score
15
Location
Newbury, MA
Doug:

With all due respect ... go tell your mechanic to read the Service Manual for that outboard. That V6 puppy was designed to operate with a anti-siphon valve in place, operating at less than 4 inches of Mercury with a fuel pump output > 3 PSIa. If anything, and you're also running a Racor type fuel/water separator, REMOVE the in-line paper fuel element that is under the cowl, right before the fuel line enters the oil pump. This should be done on all OBs with a Racor filter, as your mechanic is quite right about not leaning out the motors.

Not to be picky, but the smoke @ startup is caused by the mixed fuel that's already in the carbs. The fuel dries, leaving behind the carb covered with an oily film. You start up ... presto, oily carbs produce smoke! One way to help prevent this is to idle your motor before shutting off with the trim all the way in, motor all the way down. This raises the front of the carb and prevents "pooling" once shutoff. Then let sit for 5-10 minutes while you clean and prep the rest of the boat. The 2nd to the last thing I do when leaving is to raise the OB (I'm on a mooring), the last being shutting off the battery switch.

Another thing, OMC introduced the newer OMS (also called VRO2) oil pump on the '93 models to replace the original VRO design; OMS meaning Oil Metering System. The OMS pumps are bulletproof! I've never heard of one failing.

That myth your mechanic is perpetuating could be left over from the earlier VRO systems, "some" of which did have issues. But ... OB gurus in the know (Dunk & Seahorse et al) report that the powerhead issues that plagued the late 80s V6 motors (all brands), that were usually blamed on one component like the oil pump, were predominantly caused by the combination of:
* Poor fuel (unleaded blending, caused more ash)
* Older TCW rated oils (far less detergents)
* Overpropping the OB (lugging the motor, not high enough RPMs @ WOT)
* Zero decarboning efforts by the owner
* And sometimes, too much WOT running for extended periods.

... that combo will kill any motor ...

I'm not intending to come down on you Doug, please know that, but wow - some of the things that I hear from some mechanics and dealers are, like way out there :roll: ...
 

dougmacf

Active member
Joined
Feb 24, 2006
Messages
36
Reaction score
0
Location
Marshfield, MA
Thanks Dale,

A lot to think about when I get the boat back in the water. I'm open to info from any source so I don't mind constructive criticism at all, no problem. I listen, read, re-form ideas as I go.

I'll try the new shutdown procedure and see how it goes.
 

TomS

Administrator
Moderator
Joined
Feb 17, 2006
Messages
702
Reaction score
0
Location
Newburyport, MA
FYI,

After much internet searching and visits to the local Parker & Mako dealers and marine supply stores, I finally found the part I needed. Even the Parker dealer looked at me funny when I showed him the part.. I guess Parker hasn't used the 3/8" NPT version in a while.

It is manufactured by Moeller, and as far as I can tell is the only 3/8" NPT to 3/8" hose anti-siphon valve made. The Moeller part number is #33802-10.

The only place that I could find it was at Hamilton Marine in Maine:

http://store.hamiltonmarine.com/browse.cfm/4,27448.htm

I received mine and installed it last night.

-- Tom
 

DaleH

FOUNDER of Classic Parker Forum
Moderator
Joined
Feb 16, 2006
Messages
4,651
Reaction score
15
Location
Newbury, MA
Tempo Marine also makes them , $11.50 @ Go2Marine.com
 

TomS

Administrator
Moderator
Joined
Feb 17, 2006
Messages
702
Reaction score
0
Location
Newburyport, MA
Just to clarify, the Tempo ones have 1/4" NPT and either 1/4" or 3/8" hose barbs.

The one I needed was 3/8" NPT to 3/8" hose.

But good info for the other 99.99999% of Parker owners out there :)

-- Tom
 

stonebuster

Well-known member
Joined
Apr 19, 2006
Messages
200
Reaction score
0
Location
New Milford, CT
DaleH":2ngua25h said:
Doug:

With all due respect ... go tell your mechanic to read the Service Manual for that outboard. That V6 puppy was designed to operate with a anti-siphon valve in place, operating at less than 4 inches of Mercury with a fuel pump output > 3 PSIa. If anything, and you're also running a Racor type fuel/water separator, REMOVE the in-line paper fuel element that is under the cowl, right before the fuel line enters the oil pump. This should be done on all OBs with a Racor filter, as your mechanic is quite right about not leaning out the motors.

Not to be picky, but the smoke @ startup is caused by the mixed fuel that's already in the carbs. The fuel dries, leaving behind the carb covered with an oily film. You start up ... presto, oily carbs produce smoke! One way to help prevent this is to idle your motor before shutting off with the trim all the way in, motor all the way down. This raises the front of the carb and prevents "pooling" once shutoff. Then let sit for 5-10 minutes while you clean and prep the rest of the boat. The 2nd to the last thing I do when leaving is to raise the OB (I'm on a mooring), the last being shutting off the battery switch.

Another thing, OMC introduced the newer OMS (also called VRO2) oil pump on the '93 models to replace the original VRO design; OMS meaning Oil Metering System. The OMS pumps are bulletproof! I've never heard of one failing.

That myth your mechanic is perpetuating could be left over from the earlier VRO systems, "some" of which did have issues. But ... OB gurus in the know (Dunk & Seahorse et al) report that the powerhead issues that plagued the late 80s V6 motors (all brands), that were usually blamed on one component like the oil pump, were predominantly caused by the combination of:
* Poor fuel (unleaded blending, caused more ash)
* Older TCW rated oils (far less detergents)
* Overpropping the OB (lugging the motor, not high enough RPMs @ WOT)
* Zero decarboning efforts by the owner
* And sometimes, too much WOT running for extended periods.

... that combo will kill any motor ...

I'm not intending to come down on you Doug, please know that, but wow - some of the things that I hear from some mechanics and dealers are, like way out there :roll: ...
Dale, I switched to a racor last year and didn't remove any filter elements on my 225F. Should I have? Am I risking restricting fuel flow to motor or did I misunderstand what you wrote?
 

DaleH

FOUNDER of Classic Parker Forum
Moderator
Joined
Feb 16, 2006
Messages
4,651
Reaction score
15
Location
Newbury, MA
stonebuster":1qxpbzyc said:
I switched to a racor last year and didn't remove any filter elements on my 225F. Should I have? Am I risking restricting fuel flow to motor or did I misunderstand what you wrote?
I would remove any fuel line "in-line" filter, that if mounted would be under the cowling before the fuel pump, when a Racor is installed.

Let's just say that too much of a fuel restriction can harm a motor. I doubt you have and would like to believe your engine's diagnostics would detect a fuel restriction (OMCs & Bombs have such senors) but I am not familiar with the Yams to this point.
 

Latest posts

Top