OX66 Fuel Issues

[dsturch65]

rodbolt17 or anyone that may be able to help!

I am new to this forum but was referred from another boating forum. I am having issues with my OX66 (2001 Fuel Injected 150, 276 hours). The motor was running fine when I bought the boat a few weeks ago and again when I got the boat home. I painted the bottom and went to fire it up this weekend on the hose and had no luck. When I go to start the boat, it cranks all day but doesn't fire up. The safety lanyard is attached, and without it attached I was getting the audible alarm so I am assuming everything is working fine there.

I checked to make sure that all of the plugs are getting spark with a plug tester and all 6 lit up - dim during the day, but lit up. Also got a reading of 12.6V off both batteries. Since it turns over and was getting spark, I am assuming its a fuel issue.

The fuel filter and little plastic cylinder on the port side of the motor were full, so I pulled the hose and dumped the fuel out so it was empty. When I turned the battery on, I can hear the fuel pump turn on, so I tried cranking the motor and the plastic cylinder did not fill with fuel. Then I tried pumping by hand with the primer ball and the plastic fuel filter/ cylinder filled. I tried starting the motor again with fuel up to the filter and nothing.

I pulled the fuel hose off after the fuel filter to see if any suction was generated from the pump with the battery on or cranking and again nothing. Then I pulled the hose after the one way in-line check valve - again, nothing. Is it safe to assume at this point the fuel pump is the issue, even though it's priming? What would you recommend I try next or look at?

Thanks in advance for any help/input.

[fairdeal]

I pulled the fuel hose off after the fuel filter to see if any suction was generated from the pump with the battery on or cranking and again nothing. Then I pulled the hose after the one way in-line check valve - again, nothing. Is it safe to assume at this point the fuel pump is the issue, .

No - that tells you nothing.
On a fuel-injected outboard, you have several fuel pumps, with different functions.

The engine actually runs on its own miniature built-in fuel tank - the "VST"
holds about half a cup of gas.

inside that VST is the electric pump that supplies the injectors.

Then other pump(s) - I think your engine has 3 -
pull fuel from the tank in the boat, through the little filter bowl,
and then push it into the VST to keep that full.

Since your lift pumps are mechanical (not electric)
they only work when the engine is running.

But when you squeeze the primer bulb, YOU are filling the VST
so as long as you can feel that you have pushed as much as it will hold -
the bulb "gets hard" -
then the VST has all the fuel it needs to start the engine.

[TownsendsFJR1300]

You can spritz a little bit of PRE-MIX into the intake and see if it fires up momentarily (likely will-confirming a fuel issue).

I believe there's a small filter at the pump inside the VST, which may be clogged.

If your engine has a Schrader valve in-line going to the injectors, check for fuel pressure. Likely they'll be little.


Draining the VST, (small screw on the bottom of the unit) and catching what comes out may show crap inside there clogging things up..

[rejesterd]

Hello.

So the engine cranks fine but doesn't start.

When you say "it cranks all day", just keep in mind that you shouldn't crank it for more than a few seconds at a time. Go easy on the starter motor.

Pump the primer bulb until it feels like you can barely squeeze it anymore. That's the way to tell if the system is primed. Then see where you're at.

[DennisG01]

Fuel pressure gauges are inexpensive - that would be a great start. As mentioned, it sounds like you'll see very little pressure, if at all. But it's a good place to start, then work backwards. Now, I'm not a technician, but the next thing I would wonder is if the VST is filling (via LP pumps). Drain the VST into a suitable container and note how much you have. Then, after you pump the bulb and partially fill the fuel filter on the side of the engine (see through one... note that this is never full - maybe half-ish), go ahead and crank it a number of times - say 5 seconds at a time. Then drain the VST again and see how much you get out of it - compare to the first time. This would at least tell you if you're getting fuel into the VST to help narrow down the possibilities and it's pretty quick/easy to do.

[fairdeal]

This would at least tell you if you're getting fuel into the VST .

ehhh - disagree with you, Dennis.

it would test the efficiency of the lift pumps while cranking -
while introducing a red herring.

One of the few things a priming bulb is good for,
is assuring that the VST full when an engine will not start.

He should use that and move on with his troubleshooting.

Worry about testing the lift pumps until after the engine starts and runs.

[pstephens46]

Easiest things first. It’s getting too damn hot to be flubbering around. Wouldn’t it be nice to have a nice big covered area to work on boats?

[DennisG01]

ehhh - disagree with you, Dennis.

it would test the efficiency of the lift pumps while cranking -
while introducing a red herring.

One of the few things a priming bulb is good for,
is assuring that the VST full when an engine will not start.

He should use that and move on with his troubleshooting.

Worry about testing the lift pumps until after the engine starts and runs.

Are you saying that use of the primer bulb can push fuel past the LP's? I didn't realize that... and, quite honestly, didn't even think about it

What if we just skipped the manually pumping part and instead just went right to the cranking, then?

I think it would be pretty odd, though, for all LP's to go 100% bad at the same time, though.

[FabricGATOR]

Fuel pressure gauges are inexpensive - that would be a great start. As mentioned, it sounds like you'll see very little pressure, if at all. But it's a good place to start, then work backwards. Now, I'm not a technician, but the next thing I would wonder is if the VST is filling (via LP pumps). Drain the VST into a suitable container and note how much you have. Then, after you pump the bulb and partially fill the fuel filter on the side of the engine (see through one... note that this is never full - maybe half-ish), go ahead and crank it a number of times - say 5 seconds at a time. Then drain the VST again and see how much you get out of it - compare to the first time. This would at least tell you if you're getting fuel into the VST to help narrow down the possibilities and it's pretty quick/easy to do.

AutoZone car parts has an amazing array of test and installation tools for borrow. The have a fuel pressure test set that you purchase on a credit card and then gets credited back when you return it.
It is a neat program and had I known about it earlier, I would not have a large cabinet of specialty tools that I could easily borrow for free....

And Yes, do not crank your starter for the days end. They easily get heat soaked and after several minutes of accumulative cranking could take hours to dissipate that heat.

The LP pumps are diaphragm style and will allow fuel to push through the check valves. Leads me to ask the OP what fuel he is using?