Sea Rider
Supreme Mariner
- Joined
- Sep 20, 2008
- Messages
- 12,345
Scenario : This 2 strokes 30 HP horse is used commercially on a rib to patrol and guard a fishing fleet from non Somali Pirates, just locals. Engine is used almost all day long at ? to medium throttle, is hardly run passing 1/2 to wot throttle. The operating environment in which said engine works is far from ideal. Works on a polluted bay, lots of small floating debris, kelp, plastic bags, you name it.
The night operator caught a small plastic bag, engine overheated and engine dropped dead, not a severe overheat due to engine being at ? throttle while patrolling. After restarting the engine with muffs at shop, the peeing was very poor and intermittent, engine missed and misfired heavily through prop at idle.
Made a complete fuel circuit clean out, tank, hose, filter and carb, changed spark plugs and impeller. Idles much better than before but still misfires eventually through prop, the peeing still is not even. Powerhead peeing tube and hose are inmaculate clean.
Thermo definitely looks shot, has a dark color, was removed and thermo lid sealed without it for general testing. Engine takes about 20 + pulls to start, at fast idle water peeing port and back thermo exhaust port near stops its flow. At 1/3 throttle water peeing amount increases, at ? throttle water peeing amount increases considerably compared to fast idle and 1/3. When water pump was tested with a drill to drive the shaft, there was a nice constant neat flow, so it’s not a WP issue at all.
As this engine is used all day long and never in its life has been flushed once with fresh water, assume that all water passages are near thin, saltesclerosis issues. The prop misfire could be due to small water droplets entering combustion chamber, probably head gasket is shot too due to general overheat.
Will need to remove powerhead, clean all lower water passages located under powerhead and lower pan, remove head and remove all salt layer formed inside all water passages which lessens them and screws top internal cooling, engine works at a higher temp than ought to work, Was wondering if any other brand engine working under same conditions would achieve same overheat problems ? Will see what is found once powerhead is off and head removed from powerhead.
Happy Boating
The night operator caught a small plastic bag, engine overheated and engine dropped dead, not a severe overheat due to engine being at ? throttle while patrolling. After restarting the engine with muffs at shop, the peeing was very poor and intermittent, engine missed and misfired heavily through prop at idle.
Made a complete fuel circuit clean out, tank, hose, filter and carb, changed spark plugs and impeller. Idles much better than before but still misfires eventually through prop, the peeing still is not even. Powerhead peeing tube and hose are inmaculate clean.
Thermo definitely looks shot, has a dark color, was removed and thermo lid sealed without it for general testing. Engine takes about 20 + pulls to start, at fast idle water peeing port and back thermo exhaust port near stops its flow. At 1/3 throttle water peeing amount increases, at ? throttle water peeing amount increases considerably compared to fast idle and 1/3. When water pump was tested with a drill to drive the shaft, there was a nice constant neat flow, so it’s not a WP issue at all.
As this engine is used all day long and never in its life has been flushed once with fresh water, assume that all water passages are near thin, saltesclerosis issues. The prop misfire could be due to small water droplets entering combustion chamber, probably head gasket is shot too due to general overheat.
Will need to remove powerhead, clean all lower water passages located under powerhead and lower pan, remove head and remove all salt layer formed inside all water passages which lessens them and screws top internal cooling, engine works at a higher temp than ought to work, Was wondering if any other brand engine working under same conditions would achieve same overheat problems ? Will see what is found once powerhead is off and head removed from powerhead.
Happy Boating
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