All the outboards that I have owned or operated , "the tell tale" runs constantly from the moment it is started to the moment its switched off , with no fluctuation in between, the tell tale is what it is a constant signal to show that the motor is receiving a constant supply of "fresh water".Quote:
Originally Posted by Brambles
I have a Mariner 8hp 1998 saildrive, model 8MLSM.
Recently serviced with new impellor.
When running, the flow of water from the engine is intermittant. From full flow, the stream tails off to nothing, then after a few seconds comes back boiling hot and steaming, runs fine for a few seconds then tails off again. This is a constant thing, the cycle lasts about 15 seconds and happens the whole time the engine is running. Does this engine have a thermostat, and could it be this? Or is this perfectly normal. Any other suggestions greatfully received, otherwise back to the repair shop for another few weeks!!!
This is perfectly normal behaviour. If the engine was pumping cold water through constantly the cylinder would never reach operating temperature and warm up. The thermostat in an outboard is slightly different from a cars enclosed system but works along similar lines to keep the engine at the correct operating temperature.
This would indicate a potentially serious problem with motor cooling,possibly a blockage which clears as the pressure in the head builds up .When running, the flow of water from the engine is intermittant. From full flow, the stream tails off to nothing, then after a few seconds comes back boiling hot