help with compression
 

Engine won't start, of course. i probably cranked it too long with water intake open. When I check compression, no compression on cylinders 1 and2, a trace in cylinder 3, and good compression in 4 but spit out a lot of water. Head gasket vs flooded manifold? I closed water intake, put some lightweight oil in all cylinders, cranked it some, and am letting it sit. Any ideas?

Check the oil and see if there are signs of water there...grey oil, bubbles on dipstick, increase level. A little more history on the engines last time running would help. Did it overheat, how long was it sitting without being started, how was it running etc.

was slow to start but ran smoothly for 20 minutes while I charged battery. four or five days later, just wouldn't catch at all, with some grey water inside spark arrestor. Will check oil tomorrow.

Don't let the cylinder walls get rusty..make sure you spray/squirt oil in there, and keep the feedback from our Q's coming.

What make and model of boat? Catalina 30?

TRUE GRIT

C & C Redwing 30

Oil does indeed look gray. I drained it and will change it again. Still only have compression on #4, although I can see some valves moving in other cylinders when I crank it.

Changed oil a couple of times with oil getting clear. Still no compression on cylinders 1, 2, 3. I figure I'm looking at an engine teardown/rebuild. Much as I would like to use Moyer Marine, the logistics of getting an engine back and forth from Chester, Nova Scotia to Maryland seem forbidding. Does anyone on the South Shore of NS have a recommendation for a local shop?

With known water intrusion and bad behavior in three cylinders, I'd take the head off to assess all valves, cylinders, and head gasket. Worst case, you've got a head start, so to speak, on the necessary rebuild. Best case, the situation is contained and you're only out a head gasket and whatever stud complications arise.

With water incursion confirmed, the likelyhood of sticking valves being the culprit is pretty high. So, before you pull the head, I would try freeing the valves. Its easy but can take a lot of time. The idea is to get lubrication to the valve stems from both ends.

For the lower end, add a quantity of Marvel Mystery Oil (MMO) to the final oil change. You can replace as much as 1 quart of oil with MMO. I regularly run with 4 oz of MMO in the oil as a preventitive measure.

For the upper end, pull the spark plugs and squirt some MMO into the cylinders. Try to get an old-style oilcan with a long skinny nozzle to direct the oil towards the valves. Replace the plugs (without wires) to contain any mess from ejected oil and turn the engine over several times, either by hand or using the starter, to distribute the oil. Do this once or twice a day for several days. Then recheck the compression. Repeat as necessary. When/if you start getting compression back in 2 or 3 cylinders, try to start it. It will start hard and smoke as the MMO burns off, and run rough, but running should help work loose the last if the sticking valves.

Thanks. Will keep lubricating and cranking.

removing head not a possibility, at least not for me! MMO not available but have tried some lightweight 2 cycle oil

I have had a lot of luck getting parts from the fellows at Nova Automotive in HRM.

Peter