Beta Marine 14hp Engine Shut-Off Troubleshooting

[AmericanVagrant]

I am helping my friend troubleshoot a Beta Marine 14 hp in a Catalina 30 he recently purchased. It is a heat exchanger model which was installed "a few years ago" according to the previous owner, and allegedly has around 113 original hours on it (according to the instruments/PO).*

The basics of this problem are that after running for awhile (~10 minutes at 2500 RPM), the engine will begin intermittently hunting and eventually quit altogether. It then does not want to restart, or if it does will die shortly thereafter. Letting it sit for ~10-30 minutes is sufficient for it to restart again and run fine for another 5-15 minutes.

It is acting as if there is an overheating condition, but the temperature light never comes on the panel, the intake strainer is clear, the impeller looks good and there is a steady amount of water discharging through the exhaust. The only other possibility I can think of is a small leak in the diesel injection system which is maybe not opening up until full operating temperature/expansion has been reached.

Any thoughts on where to start with this? Beta Marine suggests clogged filters but they're relatively new. They also suggest that potentially there is grime in the tanks, but this issue occurs with exactly the same behavior whether in a calm slip or listing about on the water, so I'm skeptical of this.

[Reefmagnet]

Check the fuel tank breather. A vacuum might be forming in the tank. Check the overall fuel flow, too. I don't think it would be fitted, but an "oil alert" device kicking in might be another possibility.

[Compass790]

Yep I agree with reefmagnet, sounds like a fuel starvation problem. Check tank pickup tube, lift pump & try pressurising the system to check for leaks.Wrap joints in tissue after you pressurise it

[AmericanVagrant]

Thanks for the tips guys, I'll give that a look. When you say pressurize the lines, you many psi/bar are you talking? Any tips for accomplishing this simply?

[Compass790]

Yep you can just put an outboard primer squeeze bulb in the fuel line or a cheap 12v fuel pump which is 3-5 psi. I can get the squeeze bulb up to over 10psi easily. Search on CF forums for bleeding fuel system. Lotta people will tell you that you cant use an outboard squeeze bulb but I have been using one for 3+ years now with no issues. However ours is plumbed in so it can be isolated & its permanently isolated except when used for priming & or testing. I suspect ( but dont know) that if squeeze bulb rubber is made from same compounds as fuel lines why the panic?
But can't answer definitely for another 7 years :-)
You will have to reverse direction of squeeze bulb & block tank vent to test tank.
Hope u can get what I'm saying & that it helps eradicate yr problem.

[Siberian Sea]

Sounds like a fuel related issue. I think it’s starving for fuel from a possible partial obstruction and the fuel delivery pump is strong enough to force suck air through some weak connection. Once your engine shuts down you should see if your fuel system is in a vacuome by cracking open the top of your fuel filter chamber and listen for air suction.

[S/V Alchemy]

Originally Posted by Reefmagnet

Check the fuel tank breather. A vacuum might be forming in the tank. Check the overall fuel flow, too. I don't think it would be fitted, but an "oil alert" device kicking in might be another possibility.

My very first thought, as I had this problem on a previous boat's Atomic 4. It was spider debris partially occluding the vent line. I canged out the line from 1/2 inch to 5/8" hose, and replaced the tiny bit of screen. Problems solved.

By the way, if the engine stalls and you crack the fuel fill and hear the hiss of inrushing air into the semi-evacuated tank, this confirms a vent line clog.

[TrentePieds]

I agree. It's most likely to be a fuel flow problem, and it rather sounds as if a largish particle of dirt can be sucked UP into a constriction in the line whence it then fall away, by gravity, when there is no longer a flow of fuel to hold it in place.

I would start by cleaning the entire fuel delivery path right from tank to injector pump. Take everything apart, blow the lines clear with compressed air working BACKWARDS so that any particles in the line will be blown back whence it came. Be particularly awake to the possibility of particulate muck in the tank.

Unless you already have a facility for doing it, you might want to set up a filter near the tank - even a temporary one - through which you can circulate the fuel in the tank a sufficient number of times to "polish" it. Once you have polished your existing fuel, and you have ascertained that no more muck comes into the lines from the tank, and once you have primed and bled the injector lines, you should be good to go.

TrentePieds

[t588143]

The easiest way To check the fuel flow is to monitor the return flow to the tank. May be a near blinded fuel filter. Fuel will flow to the injection pump until the pressure has dropped enough to cause a vapor lock in the pump.

[Cheechako]

It sounds like a fuel supply problem.
-Vent line clogged (often bees/bugs nesting in the vent) One way to test is when the engine starts acting up, open the fuel fill cap and see if there is a vacuum rush when you open it.
-Fuel filter issues.
-Pickup tube end in tank clogged.

[motretu]

a permanently mounted vacuum gauge with input plumbed between fuel filter and lift pump suction side is an in expensive and handy way to monitor fuel filter heath and/or other fuel line blockages. of course, the gauge doesn't help much if the lift pump or something else upstream is the fail point. such a gauge helped me diagnose a dip tube blockage when I switched between fuel tanks [small boat won't have this option in most cases]

[dmalcol1]

Hi
Hi several years ago i installed new Nanni 40 hp in my boat installation went well but but engine would lose power and stall. The symptoms were loss of power ruff idle then stall. Restarting again would required priming fuel line I had installed inline fuel prime bulbs. My fuel tank was level or slightly above engine so last thing a thought of was inline electric fuel pump, but after installing walbro marine fuel pump I have never had to use inline fuel priming bulbs again. Problem solved!


http://walbrofuelpumps.com/marine-industrial-fuel-pump

[fiddler17]

Had similar issue all last summer and replaced exterior electronic fuel pump and racor assembly and problem still existed. New mechanic found the fitting at top of fuel tank tube was corroded and there were pin-sized holes allowing just enough air in to conk out engine. Replaced that fitting and it ran fine end of season.