2003 era 330 Anti-Siphon Valve?

[Bayhouse]

I have an intermittent engine stalling problem, sometimes one engine usually both. Alarm sounds, RPM's drop and I'm drifting. Usually at slow/no-wake or trolling speed but once last week also while running. The frequency has increased, happed 3x on my last trip. Only once have i checked the bulbs because the engines would start but immediately stall. They were both soft and a few squeezes got me running. Ran 35 miles back with no issues. Bulbs are < 2 years old, F/W filters new, and the engine filters have ~110hrs on them.

Since it's normally both engines, I'm thinking it's a supply problem. Fuel lines from the F/W separators are new, I'll going to replace the lines to the selectors and to the filters as part of this project, but don't want to overlook the ASV as a possible issue.

Could my issue be caused by the ASV?

On my 330, there's a 90* fitting into the tank and a hose barb fitting into the 90*. Which of these fittings would be the ASV?

 

[SkunkBoat]

The hose barb.

 

[Bayhouse]

Great, thanks. 3/8" on both the NPT as well as Fuel line, right?

 

[DennisG01]

Could also be a clogged vent fitting or a dip in a vent line with fuel/water in it creating the clog. Try taking the fuel cap off to verify.

 

[SkunkBoat]

Great, thanks. 3/8" on both the NPT as well as Fuel line, right?

hmmmm... I wanna say 1/4 NPT, 3/8 barb...... I might be thinking of my last boat...

 

[SkunkBoat]

. Alarm sounds, RPM's drop and I'm drifting.

the "alarm" is because the motors shut off? ...or the alarm comes first?

 

[DennisG01]

hmmmm... I wanna say 1/4 NPT, 3/8 barb...... I might be thinking of my last boat...

That's what I would think, too.

 

[Bayhouse]

the "alarm" is because the motors shut off? ...or the alarm comes first?

Hard to say, alarms are always confusing. I want to say the alarm first (2016 Zune’s) as I look at the C10 gauges and watch the RPMs wind down to stall.

 

[Bayhouse]

That's what I would think, too.

I sent a message to GW, will confirm but in the parts manual all of the ASV are 3/8 for fuel, 1/4 for the genny.

just realized, it looks like there are two pickups from each tank...what’s up with that?

 

[Bayhouse]

Could also be a clogged vent fitting or a dip in a vent line with fuel/water in it creating the clog. Try taking the fuel cap off to verify.

It’s so intermittent, this would be difficult.

 

[SkunkBoat]

I sent a message to GW, will confirm but in the parts manual all of the ASV are 3/8 for fuel, 1/4 for the genny.

just realized, it looks like there are two pickups from each tank...what’s up with that?

You are running 2 engines you need to pickup volume for 2 motors..... two hoses.... two filters

best way to be sure of threaded end is to look at one.

you can access right inside the 6" port if your tank is not full...turn OFF the 3 way valves to prevent back flow (somewhat), have a towel and container ready.
Plus, then you will know if you even still have ASVs.

 

[SkunkBoat]

Hard to say, alarms are always confusing. I want to say the alarm first (2016 Zune’s) as I look at the C10 gauges and watch the RPMs wind down to stall.

I've heard C10s don't give you codes for alarms? I'm getting the SMG4s with my new Zukes. They even put out QR codes to text to dealer. Its like they connected a laptop to your motors.

 

[SkunkBoat]

also, make sure your kill switch isn't giving you fits

 

[DennisG01]

I sent a message to GW, will confirm but in the parts manual all of the ASV are 3/8 for fuel, 1/4 for the genny.

just realized, it looks like there are two pickups from each tank...what’s up with that?

Probably referring to the fuel line size.

Two pickups would be one for each engine.

Most times, if an ASV is sticking, it can be cleaned out with Brakleen. It's just a spring/ball setup.

 

[Bayhouse]

I've heard C10s don't give you codes for alarms? I'm getting the SMG4s with my new Zukes. They even put out QR codes to text to dealer. Its like they connected a laptop to your motors.

Sometimes

I've had situations where there is an active alarm and I check the gauges, nothing is available. It may require turning the key off because later when I checked, the alarm was registered.

 

[SkunkBoat]

Sometimes

I've had situations where there is an active alarm and I check the gauges, nothing is available. It may require turning the key off because later when I checked, the alarm was registered.

check these out. These are now sold in US for new Suzukis
New suzuki gauges

Suzuki service mobile app

 

[seasick]

Its unlikely (but still possible) for both anti-siphon valves to go bad at the same time. Since both motors are affected but not always at the same time, I would eliminate for now the kill circuitry. I would lean more towards, a vent issue as mentioned or contaminated fuel. Contaminated fuel could cause clogs or just be a water issue. Second step is to take off the fuel separators and drain the contents into a glass jar. Let it sit 15 minutes or so and see what settles out if.anything.
It was mentioned to run with the fill cap off/open and that is a good/easy way to see there is a venting issue and that should be your first step.
If a vent is blocked it is easy for one motor to die and not the other since each motor probably has a little different draw pressure (vacuum) that will mean that one motor starves before the other. Depending on the amount of vent blockage, one motor mat be able to run without stalling.
Let us know what you find.

 

[wspitler]

Agree with seasick. My 330 has two tanks and I run each engine off a different tank to minimize fuel issues. I didn't see if he was running both engines from a single tank. If so switch tanks for one and see if problem follows. If they were Yamahas, I'd bet on bad fuel or clogged VST/LP filters. Several years ago I had a bad water in fuel indicator on my F250, don't know if the Suzukis have that or not.

 

[Bayhouse]

check these out. These are now sold in US for new Suzukis
New suzuki gauges

Suzuki service mobile app

Looks like a big improvement, will be interesting to see how the usefulness of the QR interface is.

 

[seasick]

I am not at all familiar with those motors so this theory is based on Yami design.

I have seen similar motor issues that were caused by two different things; In one case the owner had changed the engine mounted filter elements (in the clear bowl) but did not seat the cup and gasket correctly. That caused the bowls to suck a bit of air. Eventually the fuel in the bowl ran out and the motor stalled. You may be able to test by looking at the bowl while pumping the primer. There will be a leak OR the bowl will completely fill up. Normally it doesn't.

In the second case there were bad lift pumps (low pressure pumps). Symptoms of this condition can be starvation at low speed and/or starvation under heavier load. I don't think that is likely to happen to both motors. It would be interesting to know if your problem started with one motor only at first.

Regarding bad fuel; If there is water in the bottom of the tank but the level is lower than the bottom of the pickup, the motors get gas. When operating as the bow tilts up perhaps due to getting on plane, trim, or passenger saft, the effective depth of the water increases since the tank's bottom is now sloping aft. The water may now be deep enough to get sucked up. That water will show in the separators though and is fairly easy to check.

Another factor to ponder when you have nothing better to think about is that if there is a vent blockage, it will take longer for a partially full tank to cause starvation than it would for a full tank. On the other hand, if low pressure pumps are weak, it make take less time to act up on a full tank than an empty one (a fuller tank'd fuel level is higher and easier for the weak pumps to draw)