After the storm, Zachary and I pulled the motor on deck, cleaned and lubricated everything and drained all the sea water out of the engine and carburetor. It is a 2 cycle engine so there is no crankcase oil to change. We connected the gasoline hose and after numerous attempts we were able to restart it. The dinghy engine worked fine for several weeks, then quit. I diagnosed and electrical ignition failure and it was beyond my ability to repair. I assume that the sea water caused this. We motored to Split, Croatia and had a Mercury Outboard shop repair it for about $350. They replaced a number of electrical parts, rebuilt the carburetor, and cleaned everything then returned it in fine condition. I was very pleased.
Oh well, I had the spare parts and early one morning went to work. I was dreading this job because Mercury has cast aluminum housings bolted together with stainless steel bolts. If you know anything about mixing these metals, you know that there is a huge risk of shearing a bolt, stripping the threads in the aluminum case, or both. I took my time, used that last of the penetrating oil I had, and was very lucky...no big problems. When I disassembled the lower unit and pump casing, I found that the pump casing gasket was missing, the impeller was basically OK, and the Woodruff key that secures the impeller to the shaft was missing. My assumption was that the impeller was spinning on the shaft and because of that, not pumping water. What to do? I have no impeller key and no gasket and we are 100 miles from the unlikely possibility of finding parts.
|Cutting to the correct length|
|Dremel grinding and cutting tool - |
Shown with 4mm bolt and Impeller
|Grinding the flat side|
|Finished new key|
|Key on the Impeller|
|Flat spot on the shaft for the key|
|Impeller and Key in Place|
OK, something is wrong...I take it off the dinghy, up to the makeshift workshop on the boat...and disassemble again.
I suspected that something was blocking the copper tube that carries the sea water from the pump up to the engine. I took out my dive tank and a hose and nozzle that I recently purchased to blow things out. I had used this nozzle a few months before to blow "trash" (reconstituted corn from Eurogas) out of the dinghy engine carburetor. OK, now I am ready.
So I go through all of the steps to remove the lower unit...the same thing that I did earlier. This time is a lot quicker because those stainless steel bolts come right out of that cast aluminum housing. I had used anti-seizing grease on the bolts. Thanks, Dennis!
In no time, I am using my nozzle to blow air through the cooling system. I blow from the bottom...no joy. I blow from the top, no joy. I decide to try pumping water from the top and the bottom...no joy.
I cannot seem to find the clog, except that I now know it is somewhere in the copper pipe, or where the copper pipe connects to the engine base. It is now time to remove the mid-unit which is another cast aluminum case with stainless steel bolts. I get it done with no problems...it was truly my day in at least one area. I get the aluminium mid-unit case off and now have access to the bottom plate of the cooling and exhaust plate which is secured with more stainless steel bolts...again I am successful with these, having to use my portable torch on one troublesome bolt.
|Copper tube through mid-unit|
|Looking for the elusive clog|
I reassemble the engine...it works and pumps lots of sea water! A wonderful shower and a half hour later Judy and I take the dinghy to another boat for a really good beer. Thanks, Dennis and Virginia on Libertad for the beer!!!
And a super thanks to Judy for helping me with this difficult project.