interesting issue

[Peter]

Hi,

Boat - has not been run much in about two years. I have run it infrequently this season.

Sunday - added 16l (about 5 US Gal) of supreme fuel to the tank which was about 1/8 full. Went for a sail. Motor quit abruptly at mouth of harbour. Set sails. Got to an anchorage. Motor started no problem but would not run without full choke. Produced excellent power. On return trip to harbour we were on a broad reach in swells about 2-3 feet and we rocked and rolled quite nicely. Motor ran fine with full choke.

Monday - thinking I had some type of blockage in the carburetor, I drained the fuel bowl with the intention of trying to clean the main jet. Very carefully placed a trimmed polystyrene cup under the carburetor to do this. Fortunately, anticipating I would knock this over, I also put a thick layer of paper towel under the cup. Gas dissolved cup and I rapidly replaced the drain plug to deal with the spill. Once I had it all cleaned up and had run the blower for a good long time, engine started fine but still needed full choke.

Tuesday - knowing if i posted a question here about this without having a fuel pressure gauge installed, I installed one - easy to do and not a big $ item.

Started engine and it needed full choke again. Full pressure was maybe 2 psi and dropped precipitously when throttle was opened. Then, presto, engine started to run just fine with no choke. FP hovered between 4-5.5 psi.

Further running and monitoring of fuel pressure - you simply have to get one of these gauges for this type of trouble shooting - revealed pressure not so steady. Could drop as low as 2 psi and seemed a little jumpy.

So, I am thinking problem is either in fuel pump or somewhere upstream of the pump.

My next steps

1) connect an aux tank with nice clean gas directly to the fuel pump - start and monitor pressure - if pressure is ok, fuel pump is ok (except I seem to have the wrong pump in which produces the 4-5.5 psi instead of the 3-4.5 as recommended), if pressure not ok, bad fuel pump

I had planned to then insert aux tank prior to the filter etc, but given the state of the fuel tank, I think I will simply change the filter and clean the tank regardless.

Appreciate the keen eyes of those more experienced to see if my thinking is clear or if I am missing anything.

I have eliminated consideration of problems downstream of the fuel pump because the engine has always produced excellent power even when needing full choke.

Fuel pressure gauge was indespensible in this diagnosis - super good addition to the engine and very easy to do.

Thanks,

Peter

[joe_db]

You have a good start.
Don't get too hung up on fuel pressure. I have one pump that puts out 4.5 PSI and one that does 2 PSI. There is no difference at all in the way the engine runs between the two.
If you have erratic fuel pressure, you may have a clogged filter or you may have an air leak.
IMHO you may well have or had clogged jets. Besides for your other tests, a carb cleanout would not be a bad thing.
One more thing to check - are you developing any vacuum in the fuel system? Do you have a vacuum gauge on the filter?

[roadnsky]

What fuel pump do you have?
Also, what vessel?
The typical Facet puts out 2-3 PSI but if you have, say a Catalina 30 where the engine is mid-ship you'd need the Facet that puts out more at 3-4 PSI

[edwardc]

The only possible downside of too much fuel pressure is that it can overwhelm the float and needle valve in the carb and cause gas to pool in the carb. When running, the scavenge tube should suck this up, but with the ignition on without starting, gas can drip from the carb.

[Peter]

no vacuum gauge

vessel - ericson 29

fuel pump - facet electric but not 100%sure of model - PO told me where he purchased it and i spoke to them - they carry the 4-5.5 psi modle so suspect that is what is

thank you all,

peter

[JOHN COOKSON]

This Is Sort Of Far Out

But anyway.........
Any time you trouble shoot an electrical (or electronic) device always check the device itself and the associated electrical circuit.

Next time the pump bogs down take a voltage reading at the pump. Maybe there is something weird going on with the wiring. You can also try shaking the wiring a bit to see if the symptoms return.

TRUE GRIT

[Dave Neptune]

If the engine runs better with the choke there IS something wrong with the carb. In the installation on the E-29 2psi is all you should ever need.

Dave Neptune

[Peter]

thanks to all for useful ideas.

changed fuel filter - KRUD, KRUD and more KRUD in "old" filter.

installed new one and fed fuel system from an aux tank.

engine ran beautufully and fue pressure was very steady around 4 psi. no fluctuations with throttle application and no choke required after starting.

i have pulled the tank - Neil it is an ABYC approved tank marked to meet the appropriate standard - and will take it home to clean it.

Let me say again - the fuel pressure gauge was the critical diagnostic tool.

Somedays things go right!

Thanks again to all for suggestions and guidance. This forum is an absolute wealth of knowledge, insight and guidance!

Best,

Peter

PS - I think I will get a new fue pump just incase and the old one will serve as a nice spare.
PPS - will also pull carb and clean next week - weather is suposed to get crappy but nice tomorrow so will go sailing

[ndutton]

As I've said before, you're not done yet

Good sleuthing Peter. Now, where did the krud come from? Unless you sleuth that question out you're doomed for a repeat performance.

[Peter]

Where did it come from? Excellent question!

Boat has been sitting idle for at least 2 years, maybe three, and the PO is a PO I am working diligently to avoid becoming so I suspect a few years of careless neglect prior to that as well.

I plan on checking my vent line as well - the boat was infested with mud wasps this spring and was stored in a wooded area so I wonder if bugs were getting in that way?

Will change the filter again in a few weeks and see what that produces.

Tank is a "plastic' tank so no rust.

Thanks,

Peter

[Peter]

Sea trial today - put seafoam in with fresh gas

Engine for first five minutes or so idled up and down a bit but then settled down

Now idles pretty fast - will adjust that.

Fuel pressure nice and steady

Good power.

Started beautifully every time

Sailing was fantastic

Happy!

Peter

Thanks to all!

[Peter]

Now looking at idle adjustment

I set it up at the dock with the engine not so warmed up. It now idles quite nicely when first started.

I have to remove the choke almost instantly after starting.

After I have run the engine and motored for a while it idles fast

Will the carb set up video address this type of issue?

Thank you

Peter

[JOHN COOKSON]

Now looking at idle adjustment

I set it up at the dock with the engine not so warmed up. It now idles quite nicely when first started.

I have to remove the choke almost instantly after starting. (WHEN THE ENGINE IS WARM OR COLD?)

After I have run the engine and motored for a while it idles fast

Will the carb set up video address this type of issue?

Thank you

Peter

If you have to close the choke immediately after a cold start you are running to rich somehow. If you have to close the choke immediately after warm start this is normal.
Check the throttle and choke linkage to be sure the choke and throttle butterflies can move through their entire range.
You can play idle speed against idle mixture to find the best balance for your particular engine. Start with the idle mixture adjustment 1 1/2 turns off it's seat.
How long has it been since the distributor advance has been checked?

TRUE GRIT

[Peter]

John,

Thank you.

Throttle and choke both allow full range of motion - I will double check this though.

Distributor advance - I have not checked this and it is new to me so no idea how long. How would I go about checking that?

Timing - I have also not done the "adjust timing at cruising speed to get max rpm procedure" yet either.

Best,

Peter