Friday, April 20, 2012

I did a stupid thing

Today I changed the lift pump on the port Lehman because it was slowly pissing fuel into the pan under the engine.  As I mentioned in my last post, the red stuff in the pan has been bugging me for some time.  My white rag tied around the hose confirmed that there was fuel coming from the lift pump.  I couldn’t tell exactly where on the pump but it wasn’t a fitting so the pump needed to be changed and of course I had a spare.  As it turns out, I think it was one of George’s famous “I saved the old one just in case” kind of spares but I didn’t know that going into the project.

After I got the spare mounted and everything tightened back up I ran the engine for a while and determined that the leak was diminished but not completely banished.  Further investigation revealed that there is a goofy nylon nut arrangement on the bottom of the fuel filters that is also weeping a bit of fuel and as I hinted above, the pump I just replaced is likely one that George removed and saved but didn’t rebuild.  Whatever the situation I have a new one on order from Florida and two rebuild kits coming from Great Britain.  We’ll be well stocked once all that arrives.  In the meantime the leak is greatly reduced and I’ll keep some boat diapers tied around the two locations to sop up whatever does manage to escape.  None of this is the stupid thing I did.

While I was trying to stop the weeping fuel leak at the bottom of the fuel filters I shut off the fuel at the tanks.  Anybody wanna guess where this is headed?  I’d had it shut off when I changed the pump but that time I remembered to turn it back on. 

I ended up taking the nylon nut right off the filter housing so I could see what it was which meant that I had to shut the fuel off at the tanks.  I’d already figured out that shutting the fuel off at the port tank didn’t cut it – I’ve got a crossover that needs to be shut off too.  I messed around with the nut for a while trying to figure out how I could boogie up a cure for the completely stripped threads and finally decided that I couldn’t.  Fortunately I called American Diesel before they closed their doors for the week – they’re way over in Virginia.  We’ve got 5 of those nuts in the mail now – I like to have real spares.  I ended up putting the old nut back on and tying it up as well as I could with several nylon zip ties.  I think I actually got it stopped leaking, hard as that is to believe.  There’s not a whole lot of pressure against it but it could be 8 or 10 psi.  It just occurred to me that if it gets worse I can likely wrap some of my rescue tape around it for a temporary fix.  I may even go back and do that tonight.

Once I got everything cleaned up and put back together I started up the engine and came upstairs to take a break.  It started easily and ran fine …………. for about 10 minutes.  I was just about to shut it down and go back down below when it shut itself down.  Not good.  Seriously not good.  It almost immediately occurred to me what I had done but I’ve been around enough diesels that were ran out of fuel to know that it can either be really easy to get them going again or a real bitch.  Generally if you know the procedure its not that bad but sometimes its bad despite (or even because of) the procedure.  The first time I was around a fuel shutdown was at the University feedlot, in the silage pit which is open to the north onto the South Saskatchewan River and it was December.  It was somewhere south of 30 below and there was a wicked wind blowing up the pit off the river.  We had a medium size Massey with a Perkins diesel and we just barely got it going again before it froze up completely. 

Today I didn’t have to worry about freezing up but the process wasn’t dead simple either.  Of course I didn’t bother consulting a manual – how hard could it be?  Mechanical diesels – as I am fond of pontificating – are at their heart fundamentally simple machines.  If they turn over and have fuel they will run barring some catastrophic internal disaster which I had no reason to suspect.  As I pointed out much later to Marilyn, ours was rolling over and it clearly wasn’t running, therefore it was not getting fuel.  The question was why.  And to answer that question I am ashamed to admit I finally had to resort to reading the manual.  Father taught me that when all else fails you can read the manual so today I did.  It turns out that those two cap screws on the side of the fuel injection pump that I have looked at and wondered about their purpose, are in fact the bleed screws for the pump.  If you loosen them, pump the primer pump until they run fuel and tighten them back up the engine will start.  If you don’t do that it really doesn’t matter how many fittings you loosen – it won’t start.  I know this because I loosened pretty well every other fitting before I consulted the manual.

On balance though it could have been much worse.  Don and Darlene are scheduled to arrive here next week after I get back from Illinois.  If I had somehow managed to run us out of fuel with them onboard I wouldn’t have blamed them if they had decided to travel by bus instead.  Put me onboard a strange boat that backs away from the dock and then dies and I think I’d say “its been fun but we’ll be at the Holiday Inn for the rest of the visit.  Hope it all works out for you.”

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