Rough running

[Kelly]

Are you all tired of hearing about my problems? No? Here, I'll try a little harder...

After much discussion, testing and help, and a little bit of "resistance", my coil problems have been solved. At least I think so. Multiple engine running tests at the dock for 3/4 of an hour without any issues led me to schedule a family outing on the boat. One of the largest maritime festivals in Europe takes place every four years here in Brest so the timing was right.

The first time out we decide to just motor around the docks and ogle all the beautiful sailboats. This entails running the A4 pretty slowly, like around 1000rpm for nearly an hour. I was of course very nervous but happy to be out on the water. As we come back into the harbor the engine starts to run roughly and sounds like it's going to stall so I run it in neutral above idle and pretty much coast to our slip. We dock without incident but as I'm securing the lines, the engine stalls.

I was able to restart the engine with no hesitation albeit with subsequent rough running and stalling. After each stall, restarting is easy so I don't think this is coil related (down boys, down). Here's what I've tried since:

During rough running I've removed the spark plug wires one by one and notice a drop in performance each time. All plugs seem to be firing.
Checked the fuel in the Racor filter/water separator: no water and very little particulate matter settles out to the bottom. The gas is clear and yellow. I've never used gasoline with ethanol.
Replaced the secondary fuel filter for good measure.
Removed, cleaned and rebuilt the carburetor using the Moyer Marine kit.
Checked the recent Moyer (Autolite) plugs and all look good (dry with dusty white appearance on the tips).
Adjusted the idle mixture both leaner and richer with continued rough running.

I'm not sure what to do next. I've been wondering about the performance of the generic electric fuel pump (age? functioning correctly?) so I've ordered a new Facet pump for a replacement. I will also replace the distributor cap and rotor as I don't know the age of the cap nor what a bad one looks like. The last thing I can think of is a blocked fuel tank vent. I'll check that this evening.

I'm open for comments. Sure would like to be sailing...

[Dave Neptune]

Again?

Kelly, you may be on the right track as a "whitish" plug is a lean one. Re the rough running were you loosing power or was it just running rough? I'd also look at the centrifugal advance to make sure it is free and not stuck. A stuck advance could cause rough running but not usually a stall.
I'll say it again here a cheap fuel preassure gage in front of the carb will eliminate a lot of "GUESSWORK" and wasted "money" as all you need to do is look! Did you try the "playing with the choke" trick?
Kelly, Im heading down to Long Beach this afternoon to get a look at one of my favorite performance projects that I have been following for many years now~the "Hydroptre DCNS". I missed it at Catalina lask weekend when she went for a cruise to the Isthmus and I was just a couple of miles up the island. I had a few friends who were in the isthmus when she was there and they had no idea what or who she was. When I told them they were very impressed especially those who went on line to see what she is about. So cool!

Dave Neptune

[Kelly]

Hello Dave,

Thanks for your ideas and insight.

I'm not sure about "losing power" and "rough running". For me these are pretty much the same. When running rough, changes with the throttle make the engine cough and seem to want to stall until eventually it DOES stall. Playing with the choke didn't seem to help with the rough running but did make the engine change it's "attitude" a bit. This means that I could hear a difference but not an improvement.

As for changing the pump, I don't consider this wasted money for the reasons I stated. I would rather keep an eye on something new during my watch than always wonder about an accessory for which I have no history. I am considering the pressure gage as another add-on.

Hydroptre DCNS: The DCNS is a big employer here in Brest so we're familiar with their projects. One they are pushing now is an underwater nuclear reactor- unlimited cooling water available!!

France's favorite sailing son, Eric Tabarly, worked for a while on the hydroptre project before his untimely death (fell off of a sailboat at night). During our recent maritime festival we had the privilege of seeing all his boats gathered together. They are the Pen Duick series boats. They are all pristinely restored and have amazing stories: Tabarly was a man of "firsts".

[roadnsky]

...As for changing the pump, I don't consider this wasted money for the reasons I stated. I would rather keep an eye on something new during my watch than always wonder about an accessory for which I have no history. I am considering the pressure gage as another add-on.

Kelly-
Sure sounds fuel related.
I agree with you on your feeling of replacing the Fuel Pump.

I'm also with Dave about adding the Pressure Gauge.
Not sure of the availability in France, so I thought I'd point you to a gauge that's worked for me and it's easily ordered at Amazon.

http://www.amazon.com/gp/product/B000BWCFLO/ref=s9_simh_gw_p263_d12_i2?pf_rd_m=ATVPDKIKX0DER&pf_rd_s=center-4&pf_rd_r=1GAR64GQ03NXZ4DD4SSY&pf_rd_t=101&pf_rd_p=470939031&pf_rd_i=507846

Of course I'm not trying to tell you how to spend your boat bucks, just trying to help.

[Kelly]

boat bucks

Kelly- Of course I'm not trying to tell you how to spend your boat bucks, just trying to help.

Hi Jerry,

Dang, I thought you were going to send me one of those Nevada accessories that never seem to rust- or so it would seem in all the photos. I'm embarrassed to post any photographs of my engine these days. Everything would just look sepia toned.

I'm still looking for the gage...the one you propose doesn't seem to ship to France.

Thanks again!

[roadnsky]

I'm still looking for the gage...the one you propose doesn't seem to ship to France.

Wow, Amazon won't ship INTL?!
Hmmm, damn!
If you're not having any luck finding one, lemme know.
Maybe we can swing something where I order it and ship it to you if it doesn't make it cost prohibitive?

And there are rusty places on my boat.
(Just not as many as some)

[JOHN COOKSON]

Kelly

Are you 100% certain the choke is all the way open? Also is the flame arrestor free of blockage? Just an idea - not calling your abilities into question here......

Here's a way to test to see if you are idling or running rich at low speeds: When the engine starts to bog down shift into neutral and rev it up for 10 or so seconds. This will burn off or "unload" the fuel from a slightly too rich condition. You may see a lot of smoke out the exhaust. This will be a temporary cure until the engine "loads" up again. I used to do this all the time till I got a little less lazy and rebuilt my carb.........

TRUE GRIT

[Kelly]

Thanks for the offer Jerry. I'm off to the boat for some more evening testing. I'll let you know about the results and the gage.

[sastanley]

Mr. Gasket gauge adapter

Jerry...since we are on the Mr.Gasket fuel gauge subject..do they make adapters for the gauge with different sized fuel hose 'barbs'? I just blindly ordered the one you linked to but it is for 3/8" hose, and I am pretty sure I have 1/4".

I get plenty of time to think about it during the day, but a lot of Amazon's content is blocked at work, and then little things like this slip thru the cracks of my holey radar when I get home and have things like slowly-failing/in-need-of-service A/C unit at the house that I am babying until a HVAC guy gets out to see me with 102°F forecast tomorrow.

Kelly, good luck with your testing..should be about 5:00PM your time time give or take an hour and my ability to remember the spread and DST and all that.

Edit - looks like the only one they make..and this item is not returnable..if anyone has 3/8" fuel hose and needs this adapter...mine's for sale...cheap!

link --> 3/8" hose adapter for Mr. Gasket FP gauge

[hanleyclifford]

Finally did it

Kelly - I got tired of wondering if the polishing filter was getting plugged so I moved the pressure gauge around to be right at the carb.

[roadnsky]

Jerry...since we are on the Mr.Gasket fuel gauge subject..do they make adapters for the gauge with different sized fuel hose 'barbs'? I just blindly ordered the one you linked to but it is for 3/8" hose, and I am pretty sure I have 1/4".

Shawn-
Hmmm, I feel bad since I pointed you there.
Is it worth cobbling together a step-down arrangement?

I have one other thought...
Do you want my old Actron gauge? (It does BOTH pressure and vacuum)
I used it for my vacuum gauge until I got the much better MMI gauge.
I'm not sure of the fittings on it but will be down to the boat tomorrow and can look...

[sastanley]

no worries Jerry..not your fault

Jerry..I have the Actron gauge..which is fine for now..I still have rubber hose so it bounces around & I use it to measure vacuum.

Don't feel bad about the adaptor..it is there in plain english that it fits 3/8" hose.

I still plan to use the Mr. Gasket fuel pressure gauge and I will put it in between the polishing filter & carb like Hanley..A 1/8" NPT nipple & a 3-way female "tee" with two barbs on it and I should be good to go. I already have those parts laying around. That is next on my project list. I finally "finished" the FWC on Monday evening by draining out the plain water, Permatexing any fittings on the HX that were leaking (most of them), shortened up a few hoses and filled with 50/50 antifreeze. So, it is finished at least until I figure some way to modify it again.

Should be getting dark over in France about now...we should be hearing from Kelly soon..we did a good job of hijacking his thread!

[Sony2000]

Possibly the small jets in the venturi for idling are blocked, or timing is too early, and the points are too close.

[roadnsky]

I still plan to use the Mr. Gasket fuel pressure gauge and I will put it in between the polishing filter & carb like Hanley..

Ok, cool! Whew!

Should be getting dark over in France about now...we should be hearing from Kelly soon..we did a good job of hijacking his thread!

Awwww, let 'em eat cake!

[Kelly]

Sticky valve?

I'm back. Gorgeous weather here so it's kind of embarrassing to be testing at the dock as everyone else returns from a spin on the water...

Here's how it went last night: engine started up nicely, as usual, and I could immediately hear the rough running I've been suffering lately. I opened the gas tank fill cap with little hope as the rough running was immediate and sure enough, no change.

Then I decided to tweak the idle mixture screw a half turn toward rich (this brought me back to 1.5 turns out from the stop) and the engine seemed to appreciate this by smoothing out noticeably.

Then I ran in gear to get the temperature up and started to mistreat the engine by dropping repeatedly to idle from higher RPM but was never able to repeat the stumbling and stalling episodes I suffered.

I then let the boat pull against the dock lines at low RPM while I washed the deck and then repeated the speed changes. Everything was fine.

So, as usual, I'm at a loss but am wondering if I didn't live through an episode of stuck/sticking valve. Other than some dirt finally working its way through the fuel system, only the sticking valve would seem to be a problem that could "fix" itself.

Comments?