Primer Bulb

HotTommy

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As winter nears I'm dreaming of being on the water next spring. That got me thinking about a minor problem with the 1993 Force 150 outboard on my pontoon boat that has baffled me. .... I rebuilt the entire boat two seasons ago. That included removing and cleaning the 30 gallon fuel tank that sits near the rear of the boat. I also replaced the fuel gauge sender, filler assembly and all fuel lines including the primer bulb. I was never happy with the way the bulb felt when priming my first engine. It didn't seem to get very hard, but the engine ran well.

Last spring I replaced the first engine with my current Force 150. Getting it to run right was a long and arduous process where I frequently did not know what was causing it to be hard to start. I worked the primer bulb hard on many occasions and it never felt as hard as I expected it to feel, so I replaced it with a new one. That one felt no different. I was so unsure of its action that I started kinking the hose downstream from the bulb after every squeeze to make sure the valve in the bulb wasn't allowing gas to be sucked back from the engine as the bulb expanded. I never saws signs of excess gas leaking from the engine due to priming. .... I finally got the engine to run right (it was electrical) and it seems to be getting plenty of gas while running.

The nagging problem arose when I left the engine for a week or more. It was hard to start until I sprayed a little fuel into one of the carbs, leading me to believe it needed more fuel than the primer bulb was providing. I suppose its possible I got two bad bulbs, but I doubt it. So what else might cause a soft bulb and insufficient fuel at start up?
 

Tnstratofam

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Weak fuel pump maybe? Bad fuel line connections? It is possible to get two bad primer bulbs in a row. It happened to me with two I bought at wally world this summer.
 

foodfisher

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Fuel leaking past the carb's needle and seat would cause soft bulb and hard starts.
 

gm280

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Back in the days when I was running a Merc 115HP inline six, my fuel bulb would get hard as I primed the fuel bulb. That was quite a few decades ago now too. But I think those fuel bulbs were made out of better materials then too. I can't say that for the newer versions. But I have to believe that the new EPA standards has something to do with that also. Not know for certain, I think the EPA made new regulation to make sure fuel bulbs don't push fuel out into the carbs for that fuel to spill out and, in their opinions, polite the air. So that seems to be why fuel bulbs are built to never get too hard when priming. JMHO though! Any corrections to my think will not be taken as offensive because that is just my uneducated opinion.
 
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Jiggz

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If you haven't done so, install a clear fuel filter between the fuel pump outlet and the carb's inlet. Make the connections first to the pump outlet. Prime the fuel system up to the newly installed fuel filter before finally connecting it to the carb's inlet. This is to purge the air out of the fuel filter. Now prime the system again with the bulb and see if the fuel gets pushed upward to the carbs (you can tell with air bubbles left in the filter). If the fuel filter stays full, run the motor and watch the clear fuel filter to make sure it at least stays 1/2-3/4 full even at wot. If it stays at these level then it tells you the fuel pump is working properly or delivering the correct amount. If the clear filter empties, then it tells you there is a problem with the fuel delivery downstream of the filter from a faulty fuel pump, leaky fuel hoses, faulty check valves on priming bulb, restricted tank vent or pick up tube.

Now to test the primer bulb, disconnect the hose from the carb inlet and drain the fuel from the clear filter into a container. With the clear filter empty, prime the system with the bulb, and you should see fuel filling the clear filter. And it should only take 3~4 presses of the bulb to fill it all the way. If not then either the bulb's check valves are leaky or there is leaky hose before the bulb. You should be able to tell if there is a leaky fuel hose from the suction side of the bulb with the presence of air filling in the clear filter.

If the bulb seems to be working properly and the clear fuel filter stays at least 3/4 full, then the hard starting problem could be a choke problem. Make sure choke system is engaging when starting especially with a cold engine. Do not assume just because you heard a click when you pushed in the key that the choke is engaging. You need to verify it visually by removing the top cowl and watch it staying engaged. Most of the time, when the charge of the batter is getting low, when you pushed in the ignition switch to engage the choke you will hear the "click" telling you the choke is engaged. But as soon as you turn the switch to start, the choke disengages without you knowing it because the louder sound of the starter masks it. The reason behind this is due to lower battery charge wherein most of the current is "sucked" in by the starter which has a lower resistance than the solenoid coil. There are two options to fix this problem. One, use a bigger battery or always make sure the current battery stays full charge at all times. Second, use a relay that directly connects the choke solenoid to the battery. Kinda the same as those ones used on headlights.
 
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HotTommy

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Thanks Jiggz. I already have the clear filter so I'll try your suggestions. It'll be a while though. Too cold now to do anything but dream about spring.
 

gregmsr

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Absolutely, a weak battery will NOT fully engage the choke plunger = hard to start.
 

jerryjerry05

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A weak battery wouldn't turn the motor over.
The primer might be bad?
Unhook it and see if it's squirting when you press the choke.
The reason the bulb is soft is that somewhere the fuel is getting by.
Either one of the pumps has a bad diaphragm or the needle/ seat is defective and not sealing or the primer is allowing fuel to pass.
You can get a bad squeezie right out of the box. Tempo is one I won't buy.
You can test the one you have.
Unhook it from the tank and the pump.
Cover the tank end after you squeeze.
It should hold suction.
Sometimes for unknown reasons the fuel in the lines drains back into the tank.
You can install an on/off valve someplace in the system.
 

HotTommy

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Thanks Jerry. ... I don't know where the comment about a weak battery came from. I understand that fuel leaking by the needle can cause a soft bulb, but I don't see how that problem would be temporarily solved by spraying fuel into the carb for starting. .... From my experience, it has to be a very good battery to spin over my 150. .... I'll troubleshoot it when its warmer.
 

pnwboat

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According to my manuals, the 1993 150HP motor uses a "fuel enrichener valve" as a choke. If this is what you have instead of the older style mechanical choke that actives a separate choke plate in the carbs, you might want to verify that the enrichener valve is operating correctly.

You can tell if the enrichener valve is being energized by having someone engage the choke while you touch the valve. You should be able to feel and hear a faint clicking each time the choke is engaged.

It's a pretty simple device and operates on the same principle as the older style choke. Instead of operating a choke plate, it is plumbed to the fuel bowl of the top carburetor for the supply of fuel and operates a valve to allow extra fuel to be dumped into the carbs. The inlet line should go between the top carb and the valve. The outlet should have a line with some "T" connections that go to each of the carbs via a small barbed fitting at the base of each carb. It's not uncommon for it to get restricted due to crud in the valve assy.

The valve itself has a small black button on the top of it that you can press to open the valve. The button looks like it's 's part of the body of the valve so it's not that obvious that it's actually a button. Disconnect the intake and outlet lines to the valve and push down on the button while squirting some carb cleaner into the inlet tube. Make sure all of the small 1/4" lines between the valve and top carb fuel bowl, and between the outlet of the valve and the base of each carb are not plugged. Make sure that the barb fitting on each carb is not plugged.

Here is a picture of the enrichener valve. Note the black button on the left hand side of the picture.

Primer solenoid.JPG
 

foodfisher

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My manual went with the boat so this is out of my faulty memory. The carb/s have two circuits, idle and run. Faulty needle seat could overchoke/flood the start/idle system=hard start. Spraying mixture into the carb bypasses that and feeds the run system.?
 

HotTommy

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Thanks y'all. .... I checked the fuel enricher valve last summer when I was vainly searching for the problem that turned out to be faulty stator and switch box. It was working ok. I appreciate the explanations. As I said, I'll trouble shoot the bulb and everything leading up to the carbs. If that doesn't reveal the problem, I'll check further.
 

jerryjerry05

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The primer has a diaphragm inside it.
It shoots a bit of fuel when energized.
It can have a small hole and still work and the small hole will allow the fuel to bypass and make it hard to pump up the squeezie.
 

gregmsr

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Once upon a time, I had an issue with hard to start. The motor was turning over (probably/maybe slower than it should have been).
I noticed the choke was not fully closing...a weak "click"?....charged the battery....ckoke fully closed.....engine started fine...
 

HotTommy

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I never said I had a weak battery. I did not have a weak battery at the time of this problem.
 

jerryjerry05

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Greg, he has a different choke than you.
Tommy, someone suggested a weak battery could lead to your problem.
 

HotTommy

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Tommy, someone suggested a weak battery could lead to your problem.

I know. And it made no sense to me when I first heard it because it didn't relate to the problem of a soft primer bulb. As the non-existent weak battery issue kept popping up, I felt it necessary to put it to rest.
 

roscoe

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I have had several bad fuel line bulbs in the past.
I only buy the better rubbery OEM bulbs now. No problems.

Also, these motors are a bear to start sometimes.

Starting procedure is important.
Especially advancing the throttle handle.

There is no conventional choke on that motor.
There is a fuel enrichment valve, that releases fuel directly into the intake manifold.

Open fuel tank vent

Check the kill switch, place in "run" position

Squeeze fuel primer bulb till firm.

Advance the throttle at least 3/4 way, without putting it in gear. -- This is done by either pushing a button in the center of the controls, or pulling the shift handle toward the driver, or raising the fast idle lever, all depending on what control unit you have.

Turn the key to the on/run position.

Activate the choke (fuel enrichment valve) by pushing in on the key. The valve is only open while the key is being pushed in.

Turn the key to start while continuing to hold the key in.

Release the key and choke when it starts.

3-5 seconds of "choke", is usually enough.

Be ready to pull the throttle back toward the idle/neutral position, when the engine starts and the revs increase.

Continue to pull the throttle back as the engine warms up.

You should not have to use the choke much, if at all, once the engine has warmed up.

Engine should start within 10 seconds of turning the key.
 

HotTommy

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Thanks Roscoe. That was very helpful and I wish I had known all that last year when I first started trying to crank it. That's the procedure I got around to using and it worked fine unless the engine had been sitting for a week or more. That was when it seemed to be starved for fuel and pumping the limp bulb didn't seem to help. I can't wait for warm weather to try out what I've learned here.
 
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