When I said generators were the bane of my existence I HAD NO IDEA.
Shortly after I posted that generators were the bane of my existence we tried to start the mighty Onan and it went “unnhh”. It was hydrolocked. That means that one or both cylinders was full of some unknown liquid and when the valves closed the piston stopped moving because, as you may remember from your high school physics class, fluids are not compressible.
As it turned out I actually got really lucky – it could have been a whole lot worse. If one cylinder had fired and the other had hydrolocked we could easily have bent a rod and turned our more or less useful Onan into a poorly shaped (and even more poorly located) boat anchor.
The troubleshooting to figure out what was going on was a bear. It involved many phone calls and much online forum (SmokStak.com) guessing. Along the way I bought a whole bunch more spare parts from a guy in Washington. You gotta love anything that turns into an excuse to carry more spares.
My first step was to pull both glow plugs and spin the engine. That blew steam and water up my wrist – the wound from that is more or less healed now. When I put the plugs back in the Onan fired right up but of course the oil was pretty milky. That cleared up after a good hot run. The problem was to figure out where the unknown fluid was coming from. I didn’t think it was coolant but that seemed the only logical possibility which in turn would mean we had a head gasket leak. Part of my increased parts store now includes a head gasket and rebuild gasket kit.
The problem with the theory of the head gasket as the culprit was that:
- I wasn’t losing any coolant
- I wasn’t pressuring up the expansion tank (corresponds to a radiator)
- I wasn’t getting any oil in the expansion tank
Many of the gurus on SmokStak were pointing to the exhaust manifold as the culprit. At first I thought I didn’t actually have a water jacket exhaust manifold but my buddy in Washington straightened me out on that. All of the wanna be advisors insisted that the water jacket around the exhaust manifold was in fact raw water and therefore if the manifold started to fail I would get raw water leaking into the heads after the engine was shut down. That started to make more sense after I discovered that by simply shutting the water off between generator runs we never had any more problems with hydrolocking. Mind you I wasn’t taking any chances – I was barring the engine over every time before I started it just to be sure. Which has been a major pain in the ass by the way – it means that I can’t start the genset remotely and it involves fitting a socket onto the end of the crankshaft entirely by feel.
Today I finally got my parts shipment which includes the exhaust manifold so I tore into tearing the engine apart. I very quickly realized that, wise as they are in some matters, my SmokStak gurus are dead wrong about the type of water around my exhaust. It is in fact coolant. So I was back to square one. I finally did what I should have done a while ago and pulled the raw water impeller. Its a real genuine pain in the ass to pull so I was trying to avoid doing that. Sure enough it was missing one blade and another blade was on its way out.
I now believe that what has been happening is that the boogey impeller combined with how this generator was installed was allowing water to siphon past the missing blade and into the water lift muffler. When the water lift muffler fills up it will back up into the exhaust manifold and from there into the cylinders. That could only happen if the impeller blank happened to line up exactly right and since there was one blade out of six missing that didn’t happen very often. The Onan book says that there should be a siphon break in the raw water system precisely to prevent this type of situation. Today “Eric” at Steveston finally got around to supplying the siphon break that I ordered a week ago so tomorrow I will be able to put everything back together and I am certain it will work just fine. A new impeller alone would solve the immediate problem but the when that impeller inevitably loses a blade the siphon break will prevent a repeat of the rodeo I have had for the last week.
All of this generator drama played out as the backdrop to Grace & Al’s visit. The night of the initial hydrolock was the night before they arrived. Fortunately we were able to continue to use the generator so it had minimal impact on their visit other than the inconvenience of not being able to start the genset remotely. It was good to have Al to bounce ideas off as we jointly worked through the troubleshooting steps.
Al fixes vintage snowmobiles so I thoroughly picked his brain about my reluctant Merc outboard too. It generally runs better the more we use it but this spring it has been particularly slow to improve its performance. I’ve long believed that if any engine is running, no matter how poorly, you should leave the carburetor the hell alone but Al may have convinced me otherwise. I expect the result of me fiddling with the Merc carburetor will be that I will need to learn how to row better but we’ll see how that plays out.
Grace and Al were ideal guests. Either they enjoyed themselves or they did a very good job of pretending that they were enjoying themselves. Whatever the truth, their visit was very enjoyable for us. We introduced them to both dim sum and sushi, spent two nights at anchor in False Creek, two nights on the dock at Plumper Cove and two nights on the dock at Burrard Yacht Club. We’re still at Burrard, taking advantage of their 30 amp power while I mess with the generator. Marilyn had their laundry tied up today and will use it again tomorrow but if all goes well with the generator we should be ready to leave on Friday.