Breaking a perfectly good fuel pump

My Moto Guzzi has been run­ning pret­ty rough late­ly. It would­n’t start on my trip into San Fran­cis­co for a doc­tor’s appoint­ment the day before Inde­pen­dence Day and I had to get it trail­ered back to Alame­da. A cou­ple of months ago I had a sim­i­lar-seem­ing issue which was an elec­tri­cal prob­lem, but this did not seem elec­tri­cal. The starter motor turned the engine over with vig­or but the darn thing would not catch.

Next on my list of usu­al sus­pects is the fuel-air mix. The first thing I tried was clean­ing the pod fil­ters, which were filthy. The instruc­tions in the K&N Recharg­er Kit say that the fil­ters ought to be cleaned once every 50,000 miles. Clear­ly that is a sug­ges­tion for auto­mo­biles with K&N fil­ters safe­ly tucked under the hood in an engine com­part­ment. For a motor­cy­cle where the pods may as well be flap­ping in the breeze (and con­stant bar­rage of road grit) I’m guess­ing 10,000 miles might be a more rea­son­able interval.

After clean­ing the pod fil­ters the Nero Cor­sa start­ed up again, but I began to have the same prob­lems again with­in a cou­ple days. When I rode to a motor­cy­cle shop in Berke­ley to buy brake pads, I end­ed up unable to start the bike while parked out front of a Yama­ha deal­er. The folks at the deal­er­ship were kind and help­ful, but I could­n’t help think­ing that hav­ing an Ital­ian bike that won’t start out front is a pret­ty great adver­tise­ment for Japan­ese motorcycles.

Even­tu­al­ly I did man­age to get back on the road, and made it back to Alame­da. Trou­bling­ly, I near­ly stalled out twice while on the free­way. I even­tu­al­ly pushed the fast-idle on to keep the rev­o­lu­tions from drop­ping too low. I was now absolute­ly deter­mined to find the source of my fuel-air mix issue. Mur­phy’s law was in full effect and the bike was always start­ing with no trou­ble if I was close to home but dying and strand­ing me if I dared go far­ther than rea­son­able walk­ing distance.

Think­ing the fuel fil­ter might be clogged or the fuel pump might not be doing its job prop­er­ly, I decid­ed to go after the issue by emp­ty­ing the tank of its fuel and remov­ing the fuel pump from inside the tank. The first part after siphon­ing out the gas is to dis­con­nect the wires and hoses. The main intake and out­flow hoses are con­nect­ed by plas­tic noz­zles with quick-release fit­tings that don’t actu­al­ly quick-release. I man­aged to cut off one of the hose clamps¹The hose clamps were not meant to come unclamped. Before I cut any­thing, I bought new hose clamps which tight­en by screw. and remove the hose, but the sec­ond (on the intake noz­zle) snapped off under min­i­mal lat­er­al pres­sure. I real­ly do mean min­i­mal; I was try­ing to remove the hose clamp.

That’s a prob­lem. Get­ting Guzzi parts can take a while, which means that I would be with­out a fuel pump for who knows how long. Then when I start­ed look­ing for the replace­ment noz­zles, I found that they are not for sale. If one needs to replace one of those two frag­ile plas­tic noz­zles, the Guzzi-sanc­tioned way to do it is to replace the entire fuel pump assem­bly. That includes both noz­zles, the alu­minum mount­ing brack­et, the pump, fil­ters, all the inter­nal wiring and tubes — every­thing. That’s a $550 assembly.

Even if I had $550 lying around I would­n’t pay that much, just on prin­ci­ple. Of course I test­ed the pump by plac­ing it in a bowl of fuel and con­nect­ing it to pow­er and found that the pump was work­ing fine. There was not even any sort of clog­ging. If the pump was bad I might con­sid­er replac­ing the whole assem­bly, but I’d be grum­bling about it. If the pump itself had gone bad, I would­n’t have had to buy the whole assem­bly — the pump itself is sold sep­a­rate­ly for much less than $550 — but if I had to I would have found a way. I was not about to spend $550 on a 75¢ plas­tic nozzle.

An Inter­net search found a num­ber of peo­ple with a sim­i­lar prob­lem with var­i­ous mod­els of Guzzi. Some lucky per­son had anoth­er forum mem­ber mail a spare that had been sit­ting around, for free. There was some dis­cus­sion about the pos­si­bil­i­ty of get­ting the hole in the mount­ing plate cut with threads and fit­ting a brass replace­ment noz­zle to it.

Emo’s Auto­mo­tive Repair and Machine Shop here in Alame­da agreed to give it a try for $55, despite the fact that Emo had his dock­et full and was get­ting ready to head out for vaca­tion. He told me what I would need after spend­ing a few min­utes toss­ing around ideas and after one trip back to the dri­ve­way of Euthymia Labs (where the dis­as­sem­bled Guzzi was parked) to check the clear­ance below the fuel pump. Since a new noz­zle would have to screw in to the threads that would be cut it would have to turn sev­er­al rota­tions. A plain elbow fit­ting would not clear the out­put noz­zle as it rotat­ed. Either the replace­ment need­ed a ris­er of some sort or it need­ed to be a straight noz­zle fit­ting. Either way would require more clear­ance than the old plas­tic nozzle.

$55 is a lot to spend on one noz­zle, but of course I was not just buy­ing a noz­zle. Spend­ing mon­ey on skilled labor is some­thing I don’t mind at all. Fur­ther­more, a brass fit­ting instead of a plas­tic noz­zle will undoubt­ed­ly be more durable. Com­bine dura­bil­i­ty with sim­plic­i­ty and we have a win­ning solu­tion. Add in sup­port­ing a local busi­ness­man who does good work and we have a home run.

I scram­bled around town try­ing to get the right fit­ting before Emo closed up shop. After two auto sup­ply stores, I went to Pagano’s Hard­ware and found a noz­zle that met Emo’s spec­i­fi­ca­tions. I rushed back and found Emo’s door still open even though it was a few min­utes after clos­ing. That was Mon­day evening. He said he’d try to get to it before going away for vaca­tion Thurs­day. First thing Wednes­day morn­ing, Emo called to tell me that it was ready.

Much relieved, I picked the pump up. The new noz­zle was installed with a bit of Teflon tape and Erik Miller’s assis­tance (Erik said Teflon tape can be a lit­tle tricky.) The fuel pump went right back in, I reat­tached the hoses with the new hose clamps, plugged the electrics back in and the Guzzi start­ed right up.

Once.

Actu­al­ly, that’s not true. It start­ed fine sev­er­al times over the course of the next cou­ple days. A cou­ple times it did­n’t start right up the first time but the sec­ond time I tried it it fired up. I fig­ured that was some­thing I ought to keep my eye on in case it got worse. I need­n’t have both­ered pay­ing it any atten­tion because Sat­ur­day evening when I went to pick up some pre­scrip­tions from the Cost­co phar­ma­cy in San Lean­dro it start­ed per­fect­ly, got me as far as San Lean­dro, and then would not start once I fin­ished with Costco.

I spent over two hours at Cost­co try­ing to bump­start the Guzzi, try­ing to trou­bleshoot the fuel line, and look­ing for any elec­tri­cal issues. I was get­ting nowhere both lit­er­al­ly and fig­u­ra­tive­ly until help (Matt Fe2O3 who answered my SOS on the Bay Area Rid­ers Forum) was a few min­utes away. A Cost­co employ­ee who was leav­ing work offered to push the bike to help me bump­start it, and this time it worked. I called back Matt and told him that he could go home but he sug­gest­ed that he come along any­way to fol­low me and make sure I would make it home safely.

Good thing he offered because I got out onto Doolit­tle Dri­ve and felt the bike hes­i­tat­ing. It was almost — but not quite — like run­ning with only one cylin­der fir­ing. It felt as though it was fail­ing to fire one time out of every three. Then almost with­in sight of the Bay Farm Island Bridge the Guzzi sput­tered to a stop and would not start again.

Matt brought out a bat­tery (even if there was no prob­lem with the charge before I spent two hours turn­ing the motor over with­out the engine catch­ing, it was almost cer­tain­ly low now) and we start­ed trou­bleshoot­ing and test­ing, this time quite lit­er­al­ly at the side of the road with Mat­t’s SUV’s blink­ers on.

More than an hour lat­er (it was 9:30 and we were work­ing by flash­light) the bike mys­te­ri­ous­ly start­ed run­ning. We began pack­ing up the tools but just as the seat went back on the bike and we were get­ting ready to go the bike stalled out com­plete­ly and again would not start.

We pushed the Guzzi to the Park ‘N’ Ride by the Chuck Cor­i­ca Golf Course after I con­sid­ered how fun push­ing the bike two miles home would be. Once the Guzzi was locked down in the lot, Matt gave me a lift the rest of the way to Alameda.

I returned to the bike ear­ly on Sun­day with Erik and a mul­ti­me­ter. After con­firm­ing that it seemed like a fuel star­va­tion issue we got a bot­tle of injec­tor clean­er and poured it in the tank, hop­ing that if the injec­tors were clogged that maybe we would luck out and get the bike to run for a minute or two again, long enough for some of the clean­er to make its way through the system.

After tak­ing a break with a refresh­ing Arnold Palmer²50/50 mix of iced tea and lemon­ade. The Arnold Palmer might be called the refreshingest bev­er­age on Earth except that «refreshingest» isn’t a real word. we went look­ing at the electrics. Electrics had been high on the list of caus­es as the whine of the fuel pump cycling up could only some­times be heard when the igni­tion key was turned. Erik read the elec­tri­cal dia­gram from the shop man­u­al while I turned the igni­tion key on and off until he fol­lowed the fuel pump cir­cuit back to the relays.

We had swapped the fuel pump relay with relays from oth­er posi­tions three times before the test­ing with the mul­ti­me­ter began, and swap­ping the relay had not done any good. But there was still one relay that had not been swapped in to posi­tion to make it the fuel pump relay, so we gave it a go.

Bike start­ed right up, no trou­ble. It kept run­ning, no trou­ble, all the way back to Euthymia Labs. There it start­ed again and ran fine all the way home. No stalling, no hes­i­ta­tions, no mis­fires. Today the bike has again been run­ning well. It accel­er­ates more smooth­ly than it has in months, sug­gest­ing that the relay had been slow­ly flak­ing for some time.

I ordered a bunch of relays from Design­Tech Engi­neer­ing that should keep me in spares for a while. Until then, I hope that what­ev­er flaky relays I have plugged in are non-essen­tial enough that I’ll get by until my relay ship­ment arrives.

For now I’m glad to know that I have at least one fuel noz­zle that is unlike­ly to break if I look at it too hard. I’m a lit­tle mad at myself for break­ing the noz­zle in the first place. It’s a tad frus­trat­ing that I man­aged to break a part that was­n’t even mal­func­tion­ing. I had more to fix after I start­ed repairs than I did when the bike sim­ply would­n’t run.

Then again, if fix­ing motor­cy­cles was easy, every­one would be doing it.

• 1
  The hose clamps were not meant to come unclamped. Before I cut any­thing, I bought new hose clamps which tight­en by screw.
• 2
  50/50 mix of iced tea and lemon­ade. The Arnold Palmer might be called the refreshingest bev­er­age on Earth except that «refreshingest» isn’t a real word.