primer bulb flat

[uncwredfisher]

I just replaced the bulb for my fuel line on my mercury engine. I ran it today and It ran fine but noticed that the bulb was sucked down and pretty much flat. What could this mean? I ran 15 miles and it did fine and noticed that after I got back home from trailering the boat, the bulb had expanded back out. Any ideas. Would have mean I have an air leak or something is too tight? Thanks

[Tyee 2]

Sounds like your fuel tank vent is blocked, or maybe closed if you run a portable tank.

Good luck... Tyee.

[jethro1]

It means there is a restriction somewhere in the fuel supply system between the outlet of the bulb and the fuel. Since you replaced the bulb it is probably upstream of the bulb. Could be the following, or something else:

Crimped fuel line (too tight of a turn)
Internal failure of fuel line (inner wall collapses and shuts off fuel flow)
Bad anti-siphon valve (remove the damn thing and throw it as far as you can)
Fuel shut off valve (if equipped) has vibrated closed or otherwise been moved to the closed position
Fuel filter (if equipped) has blocked filter
Fuel pickup tube screen (if equipped) is clogged with debris
Fuel pickup tube clogged with debris
Fuel vent is blocked

[warthog5]

The other guy's forgot 1. How about the new bulb?

Just because it's new, doesn't mean it's worth a damn.

Did you buy a Tempo fuel bulb? They are known to be the worst one's.

[Sea_Dad]

did you put it in backwards or kink the hose? Check the hose to make sure the inner liner of the hose didnt get separated and shoved up in the hose when you put the bulb in.

[uncwredfisher]

I did use the new tempo bulb. I did not know they were that bad. Should I change. I talked to a guy and he said OMC makes a good bulb. I have another question. I was also told that the bulb needs to be going upwards at a 15 degree angle or more. However, the way I mounted my fuel/water separator it is tough to get the bulb in this position. I do have a main line coming up to my splash well that later feeds into my water separator. Is it ok to put the bulb under the deck and cut into that line and just run a straight line from the separator to the engine? It is a 3/8" line which is a bigger hose than the one coming off the water separator above deck. If you do put the bulb down there, can it push enough gas through the separator up to the engine or do you want the bulb after the separator. Sorry to be so confusing. I appreciate all the input

[cfwegman]

I think Tempo gets an unfairly bad wrap.** Use the up angle advice*where the bulb needs to be WHILE you are squeezing it and I've never seen any brand of bulb not work fine. the little one way flow valves in the Bulbs often only pump gas correctly when held inlet low outlet high. They need to pull gas up into the bulb and expel it up and out from the top.** then it can lay any which a way after you have pumped it. all you are doing is making sure you have fuel to the carbs/injectors. Once you have solid fuel in the line from the pump in the motor back to the tank the fuel will pull into the motor ok even if the line is up, down, long short etc.

[the snafu]

i have seen the hoses get a small air leak and cause them to suck flat

[Mumblerone]

"Bad anti-siphon valve (remove the damn thing and throw it as far as you can)" Not a good idea! The anti-siphon valve is there for a very good reason! If a line should be cut (or burnt off) for any reason to the motor; this valve keeps the gas from running out of the tank...all of it. It is also a USCG requirement.* In a gas fire, I would also think one of the first items the insurance adjuster would check, too.* It is a very simple devise, check it. It is nothing more than a spring and a ball in the fitting; at the gas tank usually. Looks just like a right angle fitting. If gummed up, it will stick; but seldom fails...easy check.

I'm not so sure Tempo gets a bad rap...have you taken them apart? The OEM (Evinrude) has a ball and spring in both sides...the Tempo has a flapper valve in one side (if I remember right). I would also be sure to have them installed with the arrow up...this may require that you put a 'loop' in the gas line. Good luck! Keep us posted.

[jethro1]

Mumblerone,

Think about it for a second. In the case of most outboards (if not all) the engine and the fuel lines are above the fuel tank. For a siphon to occur the fuel line has to be below the level of the fuel. Since the fuel lines are above the maximum level of the fuel in the tank, if a fuel line break were to happen the fuel will simply flow back into the tank. There cannot be a siphoning of fuel.

Is it a good idea to have a siphon valve installed? Maybe, maybe not. My personal opinion is they cause far more problems than they would ever prevent, particularly in an outboard engine installation.

And by the way, here is what the Coast Guard has published concerning use of anti-siphon valves:

Quote
This pamphlet, ?SAFETY STANDARDS FOR BACKYARD BOAT BUILDERS,? (COMTDPUB P16761.3B), is a simplified explanation of Federal recreational boat construction requirements and is intended for the use of the non-professional, individual builder. The primary objective of these requirements is to avoid certain safety hazards which have been found to be the cause of boating accidents.

Each fuel line from the fuel tank to the fuel inlet connection on the carburetor must be above the level of the tank top OR HAVE AN ANTI-SIPHON DEVICE OR AN ELECTRICALLY OPERATED FUEL STOP VALVE. End quote.

The full text of the Coast Guard publication can be found here:

http://64.233.161.104/search?q=cache...irements&hl=en

Note that I have emphasized in capital letters the key part of the text. It is an either/or situation. Either have the fuel lines routed above the top of the tank OR use an anti-siphon valve. The Coast Guard does not mandate use of an anti-siphon valve.

Another one for the myth busters file.

Here is the actual law concerning use, or non use, of anti-siphon valves:

FEDERAL LAW

183.568 - Anti-siphon protection

Each fuel line from the fuel tank to the fuel inlet connection on the carburetor must:

(a) Be above the level of the tank top; or
(b) Have an anti-siphon device or an electrically operated fuel stop valve:

(1) At the tank withdrawal fitting; or
(2) Installed so the line from the fuel tank is above the top of the tank; or

(c) Provided that the fuel tank top is below the level of the carburetor inlet, be metallic fuel lines meeting the construction requirements of Sec. 183.538 or “USCG Type A1” hose, with one or two manual shutoff valves installed as follows:

(1) Directly at the fuel tank connection arranged to be readily accessible for operation from outside the compartment, and
(2) If the length of fuel line from the tank outlet to the engine inlet is greater than 12 feet, a manual shutoff valve shall be installed at the fuel inlet connection to the engine.



"Anti-siphon protection” is a term applied to the means of preventing the siphon action of permitting fuel to continue to flow out of the fuel tank in the event there is a break or rupture in a fuel distribution line, or if a fitting in the fuel line loosens, creating a leak.

"Anti-siphon protection” may be accomplished by one or more of the following methods:

(a) Keep all parts of the fuel line from the fuel tank to the fuel line connection at the carburetor above the level of the top of the fuel tank. The tank top level is determined with the boat in its “static floating position.” Practically, the fuel pump and fuel filter(s) must also be above the tank top.

(b) Install an anti-siphon device at the tank withdrawal fitting. The fuel distribution line may then run below the level of the tank top. A filter may be installed between the fuel tank withdrawal fitting and the anti-siphon device.

NOTES:

Some anti-siphon devices are spring loaded check valves. These valves have a specific cracking pressure and provide protection up to a specific head. Therefore, the anti-siphon valve must be selected or ordered to protect against the siphon head for a particular installation.
Too high a cracking pressure may cause vapor lock. This has become an increasing problem with reformulated gasoline (RFG). Be sure to select the correct cracking pressure.
Some anti-siphon devices involve a bleed hole in the fuel pick-up tube, near the top of the fuel tank. The size of the hose is critical for a particular application. Each installation using this type of protection must be evaluated to assure its effectiveness. Too large a hole will bleed excessive air into the fuel flow effecting engine operation. Too small a hole may not stop fuel flow in the event of a fuel leak. This installation is used very infrequently because of inherent problems that may result.
(c) Install an anti-siphon device at a location where a line from the fuel tank will no longer remain above the fuel tank top level. The anti-siphon device will then protect the portion of the line that must run below the tank top level. The portion of the line that is above the fuel tank top level will be automatically taken care of.

(d) Install an electrically operated fuel stop valve at the fuel tank withdrawal fitting. This valve requires electrical power to open and must be connected to operate only when the ignition switch is on. A filter may be installed between this valve and the fuel tank withdrawal fitting. Electrically operated fuel stop valves must comply with 183.528.

(e) Install an electrically operated fuel stop valve at the point in a fuel line where it must run lower than the fuel tank top level. This valve requires electrical power to open and must be connected to operate only when the ignition switch of the engine it serves is on. A filter may be installed between this valve and the fuel tank withdrawal fitting. Electrically operated fuel stop valves must comply with 183.528.

NOTES:

Fuel stop valves used in the fuel system, whether electrically operated or manually operated, must withstand the 2-1/2 minute fire test in accordance with 183.590.
Anti-siphon devices are not required to meet a fire test.
The fuel stop valve is required to be directly at the fuel tank connection by 183.568(c)(1) and must be installed so that it can be operated from outside the compartment. This can be accomplished with a reach rod or a long valve stem. The installation of an access panel over the valve is also permitted. However, once open, the valve must be immediately accessible inside the panel so that the operator does not have to reach through fire to shut off the fuel.
FIGURE 34 - Anti-Siphon Protection

TO COMPLY WITH THE LAW

Is the fuel distribution line above the fuel tank top level?
If not, is an anti-siphon device or an electrically operated fuel stop valve installed at the fuel tank withdrawal fitting?
If not, is an anti-siphon device or an electrically operated fuel stop valve installed at the point where the fuel distribution line goes below the fuel tank top level?

[Mumblerone]

"Is the fuel distribution line above the fuel tank top level?"* Mine is and I have anti-syphon valves, too.* Now why do you think Boston Whaler did that?* All your points are well taken.* Great discussion.*

As a small example:** When I checked my anti-siphon valves on the trailer; I took the hose off...no gas came out of the valve.* I then proceeded to take the anti-siphon valve off to check it...gas started pouring out of the full tank into the bilge.* I immediately retightened the fitting.* Obviously the tank was not perfectly level, but the valve worked.* I guess I would caution (based on your homework, which is great)...than a person should be vary cautious disgarding a anti-siphon valve installed by the manufacturer.*

This would be my main reason for disagreeing with your intial statement.* Thanks*

[FreakAustin]

warthog5 - 6/17/2005 8:00 PM

The other guy's forgot 1. How about the new bulb?

Did you buy a Tempo fuel bulb? They are known to be the worst one's.

I had one of these on my Johnson 150 and it flattened causing me to lose my top 2 cyls due to no gas in the top carb.

[peter blackman]

I once put a new Tempo bulb /fuel line in my boat , couldn't believe the new bulb was the problem and spent hundreds of dollars chasing non-existent problems until I swapped out the new tempo as there was nothing else to change. Everything said about tempo bulbs is true, I know some reputable boat suply stores wont stock them. As a result of my bad experience I wont buy any tempo product as matter of principle .
If you read the boards the problems these bulbs cause are continous, stores should not stock them to protect unsuspecting buyers. I dont know what the rest of the their product line is like but I dont intend to find out.

[surfri]

freakaustin what year was your johnson. i am having the same problem with mine. it's a 2004 and the check engine alarm keeps coming on do to a gas striction. how long did you run it until you realized you lost your two cylinders?

[uncwredfisher]

hey guys, sorry i have not posted again. I have been out of town. I went to the store today and got the OMC bulb and am going to try that one. Stinks i spent the money at boaters world for the other bulb. I will put it on and see if I get better results. Thanks for all the input and advice. I hope to get her right soon