Losing prime

[awthacker]

We had a great boat ride last weekend... 50+ miles with no problems. Yesterday we rode about 12 miles out, anchored for maybe 2 hours. Then after pulling up the anchor and turning in, we get on plane for less than a minute and the engine dies. I restart and rev... seems okay... give it some gas and it dies. We idle in some 2 hrs at 6-8 mph. Once inside the inlet, I decide to tinker a little and find that the primer bulb is not firm. I squeeze it and the engine accelerates. Then trade places and have the wife back there squeezing intermittently while I drive and the boat runs great for the last 1/2 mile stretch. So the problem seems to be getting fuel to the engine.

After deep thought last night, I'm thinking it may have something to do with the fuel pump. I disabled the VRO pump personally by plugging the oil-in nozzle and disconnecting the wiring harness to the VRO. Could this be causing the fuel pump to malfunction?

I also plan on replacing the primer bulb and the fuel supply valve (it's a three way valve that would've allowed me to divert fuel to the kicker engine, which is no longer installed on the boat - I was going to replace it with a union, or splice because I only have one tank and one engine), but how can I check the fuel pump for proper operation? Should I plug the VRO harness back in, even though there's no oil supply to it? I remember having read that the proper way to disable VRO was to buy a new fuel-only pump rather than disable half of it.

Thanks,
Aaron

[awthacker]

The fuel filter seems clean and the water sperator is new, having 6-7 hours on it. Just wanted to rule these out as potential problems. The fuel is fresh and properly mixed at 60:1.

[awthacker]

Here's what I was thinking of regarding the fuel pump, but I don't wanna buy it just to be a parts changer.

http://www.marineengine.com/newparts/part_details.php?pnum=OMC5007422&ptype=&Engine=&Model=

[tsubaki]

Seems I looked at a VRO on a 3 cylinder that would require you to keep the wires connected in order for the fuel pump to work or you would have to completely remove the VRO system, tap into the plug in the block in order to get a vacuum line and then install a regular vacuum type fuel pump.
Reconnect the wires and see if the problem disappears. Chances are there is a signal wire to the oil pump that will set off the low oil alarm, if so you may need to cut that wire.
The link to you provided to the premix pump looks like an easy solution.

[Cam]

Sounds to me like there is some sort of fuel restriction. It may be a collapsing fuel line, which has become quite common with this ethanol gas. Check all the lines and if possible, run it off a seperate (5 gallon) fuel tank to see if you get the same restrictions.:head:

[Destroyer]

Check all the lines and if possible, run it off a seperate (5 gallon) fuel tank to see if you get the same problems.:head:

That would be my first suggestion also. That instantly rules out all fuel lines, dirty filters, etc. Then you can make a better informed decision based on the results. :head:

[aussie]

im no expert but it sounds like the fuel pump is sucking air from somewhere i would put a fuel pressure gauge and check fuel pressure
could be a seal on the fuel system from the tank to the fuel pump not sealing not sure if your tank has a screen on the fuel pick up and sometimes when replacing fuel fiters dirt can get in the fuel line check the fuel pump may have dirt in the one way valves

[nymack66]

Process of elimination, run it off a portable tank as posted, disconnect it from the top of the current fuel tank. Connect this hose to the portable tank if all is well its the fuel pickup strainer in the tank or the anti siphon valve on top of the tank.
You mentioned 60:1 mix it should be 50:1 Typo?
You ran this motor perfectly before so I don't this its anything to do with the disconnecting the vro ...
Be careful not to run it at WOT with a fuel starvation you will blow the power head ...

[tsubaki]

awthacker, please refresh my memory.
I had it in my mind you had cleaned the tank, replaced the fill hose and the fuel lines to the motor and added the water separator prior to or during your repower.

[bradford]

There was a thread a couple of years ago when Hammer had this same problem.

His ball would get soft and he'd have lefty squeeze it and it would get hard again. LOL!! :zip:

Where's old Hammer been? I miss him. :sad:

[awthacker]

awthacker, please refresh my memory.
I had it in my mind you had cleaned the tank, replaced the fill hose and the fuel lines to the motor and added the water separator prior to or during your repower.

Cleaned the tank, replaced the fuel lines, left the primer bulb because it looked new, did not replace the fill hose or air vent hose, replaced water seperator.

[awthacker]

Today I reconnected the VRO wiring harness, replaced the primer bulb, and bypassed a fuel shut-off valve. I brought along a 6.6 gal pony tank. The boat idled nicely through the no wake zone, then planed up nicely before dying out back to idle speed while at 3/4 throttle. My buddy pumped the bulb and it picks up again. We switched to the pony tank and have the same problem. Tomorrow I'll inspect the fuel pump for blockage.

[awthacker]

Seems I looked at a VRO on a 3 cylinder that would require you to keep the wires connected in order for the fuel pump to work or you would have to completely remove the VRO system, tap into the plug in the block in order to get a vacuum line and then install a regular vacuum type fuel pump.
Reconnect the wires and see if the problem disappears. Chances are there is a signal wire to the oil pump that will set off the low oil alarm, if so you may need to cut that wire.
The link to you provided to the premix pump looks like an easy solution.

There was a low oil alarm when the wiring harness was connected. But the engine still stalled. So the harness is disconnected again. I have run it this way for maybe 5 hrs prior to the problem.

[tsubaki]

And with the engine off, you can pump the bubble and it stays hard?

[Cam]

What happened to me personally, my fuel pump diaphragm split and kept flooding the engine. Sort of the same symptoms you have. Once the daiphragm broke, it kept flooding the cylinders when I pumped up the ball. Take off the cowl and while pumping the ball, watch to see if fuel is pouring through. When this happened to me, ball would not get hard after pumping it up. If this is the case, you will need a new fuel pump. Unfortunately, big $$$$. Good luck and keep us posted.

[tsubaki]

That was my next thought or the carb needles aren't seating or the floats are out of adjustment.

[aussie]

dont no if u like my idea but if the pump is very expensive u can put a electric fuel pump on it i think there only wort $50.00 and the good thing is u dont have to prime the bulb each time to start soon as u turn on the ignition the carbs r full we call them a solid state fuel pump here is a pic

http://cgi.ebay.com.au/Electric-Fuel-Pump-12-volt-Solid-State-4-6psi-130-LPH-/130489497518?pt=AU_Car_Parts_Accessories&hash=item1e61c7b7ae

[awthacker]

dont no if u like my idea but if the pump is very expensive u can put a electric fuel pump on it i think there only wort $50.00 and the good thing is u dont have to prime the bulb each time to start soon as u turn on the ignition the carbs r full we call them a solid state fuel pump here is a pic

http://cgi.ebay.com.au/Electric-Fuel-Pump-12-volt-Solid-State-4-6psi-130-LPH-/130489497518?pt=AU_Car_Parts_Accessories&hash=item1e61c7b7ae

Not that I think yours is a bad idea, but this morning I ordered the OEM fuel mix pump that comes w/out the VRO.

Also, yes, my bulb does go soft while resting. Sometimes it takes like 20 squeezes to get it firm. I have also seen fuel leakage through that little red switch (manual choke lever?) when squeezing the bulb. I just assumed that was a normal symptom of over-priming or flooding.

[tsubaki]

The manual prime/choke may leak at times. For the most part it just scoots gas past the carbs and into the throat of the carbs, but usually leaks when rotated.
Being you bought the part to dismiss the VRO and have the fuel mix retrofit, let us know how it did.
On another note, you might have needed 2 fuel pumps at a cost of $80-$100 each. Also having to need to derive a vacuum siphon for the pumps and having to made a mounting bracket for them. The cost of the fuel mix pump ain't that bad considering the aggravation of the other installation.
aussie's electric pump idea will work but I've always been afraid of that installation.
While you are waiting, remove the stuff to and from the pump, reconnect to the carbs (if possible without a bunch of aggravation) to see if the floats are seating when the bubble is primed.

[aussie]

Not that I think yours is a bad idea, but this morning I ordered the OEM fuel mix pump that comes w/out the VRO.

Also, yes, my bulb does go soft while resting. Sometimes it takes like 20 squeezes to get it firm. I have also seen fuel leakage through that little red switch (manual choke lever?) when squeezing the bulb. I just assumed that was a normal symptom of over-priming or flooding. well if the fuel line is draining back it sounds like the one way valve in the pump is not sealing its like having a hose full a water and holding your finger on it the water will stay in the pipe take your finger off and it drains out

[spareparts]

if you think about it, the primer bulb will not stay hard if you are running the engine, the fuel pump pulls a vacuum on the line, which overrides the antisiphon valve in the tank, drawing fuel up thu the line. It will draw fuel out of the line/primer bulb till the vacuum overcomes the anti siphon valve or the resistance in the length of line/height of fuel drawn. the only time the bulb is completly hard is when you prime it up to a point of pressue ahead of the bulb against the seats in the carb. Its normal for the primer bulb to not be hard after you run the engine, for that matter, its normal for it to be soft after it sits for a long while, the check valves are not that good in a primer bulb. I do recomend using only an OEM primer bulb, either Merc/ yamaha/ or Bombardier(OMC). I have thrown dozens of fairly new Moeller and Sierra primer bulbs in the trash

[awthacker]

I do recomend using only an OEM primer bulb, either Merc/ yamaha/ or Bombardier(OMC). I have thrown dozens of fairly new Moeller and Sierra primer bulbs in the trash

So where do Perko (the old one) and Attwood (the new one) fit into the primer bulb hierarchy? lol.

[spareparts]

if its not an OEM, it fits in the trash can

[Steplift 72']

If it's old "winter gas" and you're now above 70F it might be as simple as vapor lock. Refineries blend gas differently with more C4 for winter months so it'll kick off in cold temp's. I've had a soft bulb and an engine that would bog above 2500 rpm because I was running winter gas out of the boat in spring. I ended up pulling the anti siphon valve out of the fuel line so I could burn off the old gas without vapor lock. The butane is volatile and creates lots of vapors on a warm day. Hope it's something simple.

[awthacker]

If it's old "winter gas" and you're now above 70F it might be as simple as vapor lock. Refineries blend gas differently with more C4 for winter months so it'll kick off in cold temp's. I've had a soft bulb and an engine that would bog above 2500 rpm because I was running winter gas out of the boat in spring. I ended up pulling the anti siphon valve out of the fuel line so I could burn off the old gas without vapor lock. The butane is volatile and creates lots of vapors on a warm day. Hope it's something simple.

If a $315 fuel pump qualifies as simple, then it was. It was definitely the easiest part to change out. We ran the boat 30 miles on Saturday without any problems.

[Destroyer]

If a $315 fuel pump qualifies as simple, then it was. It was definitely the easiest part to change out. We ran the boat 30 miles on Saturday without any problems.

Ouch on the $315.... congrats on the running on Sat without problems. :beer:

[awthacker]

Thanks Destroyer.

There was a low oil alarm when the wiring harness was connected. But the engine still stalled. So the harness is disconnected again. I have run it this way for maybe 5 hrs prior to the problem.

I wanted to point out that the replacement fuel pump I installed was designed for pre-mix and therefore didn't have the VRO (oil) side to it. What intrigued me was that there was no electrical harness. So I guess fuel pumps operate simply on vacuum and not electricity?

[bassarama]

I had a similar problem, please read my thread and look at the pics, like they say; a pic is worth a thousand words...


http://www.wellcraftv20.com/community/showthread.php?t=14311