Re: 20 hp Yamaha safe to run??
Early Sunday morning it was about 20* and we were starting 4 outboards that had been outside all night, from 25-70 hp; OMC and Yamaha. None of them pissed at first due to ice in the hole. One guy disconnected his hose from the fitting and found it running fine. All eventually thawed and pissed.
The pisser is just an indicator but it gives false negatives. If it's not pissing there MIGHT be a problem, but more likely it's a clog. Your overheat alarms and governors protect you too, if they are working. To be safe, you want it working to know that your water pump is working, but it isn't neccessary. If it's not working you are taking a chance there is a failed water pump or clogged intakes, but not necessarily so.
To avoid the problem, you could disconnect the hose from the fitting after use and drain it, and leave it disconnected, until you are ready to run; at that time verify that the hole is clear. Keep a piece of wire handy to ream it out. On an old 70, my fitting broke, so I just ran the hose out the hole and put a cable tie on in to keep it outside the cowl. I am not aware that any back pressure is required.
Check you intakes for ice on their surface. Store your motor down to drain water in the lower unit, but it's OK to trailer it up as long as it has been drained.
If you keep your boat on a trailer/lift in freezing weather, but take it out: watch out for frozen bilge water. First, drain your boat by removing the hull plug. But water freezing in a bilge or inside fittings can crack your through-hulls, sea cocks and pumps, and you won't know until too late. Water around the bilge pump can freeze its impeller and water in its hose can block it. If you turn on a frozen bilge pump, it might sound OK but you might have a broken shaft. So before you leave the dock, dump some water in the bilge and test the float switch and verify that it pumps that water OUT. Check your bilge after you depart the dock but before you get too far out.
A 21' Grady sank in the Bay just before New Year's b/c its raw water pump for the live well blew apart. Had been on the trailer/lift during freezing temps. Everyone survived b/c they could jump onto a nearby boat when they realized what happened. Live and learn.
