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40hp 4 stroke efi tiller

G

gone4x4

New member
I am having and on going issue with my engine sounding an alarm and shutting off while running. yesterday morning, we were fishing the middle of the lower Potomac, overcast, hardly a breeze (or fish for that matter:eek:) we decided to make a run up river to another spot about 20 minutes to get there no problem. fished off the electric motor for about 2 hours, and then headed back to where we started. by now, the air temperature and humidity was up to the low to mid 80's, we ran just off full throttle for about 25 minutes, when the overheat alarm sounded and the engine shut-off, plenty of water coming out of the pee hole no debris on the lower unit. shut it off and restarted ok and idled ok, try'd some throttle and it started missing and shut-off. pulled the cowl off, waited about 10 minutes, started up fine and went to another spot, about a 10 minute run-cowl-off and closer to the ramp. fished on the electric motor for another hour, it started to rain, put the cowl on, rain stopped, ran to the boat ramp and drove it onto the trailer no problem?? any I-deers?
 
impeller replaced? check. thermostat replaced? check. temp sensor replaced? check. still goes into overheat mode if and when, I am running with the engine cover/cowl on, remove it and place it in the bottom of boat, engine runs fine.??
 
Have you tried a different fuel tank? It may not be an overheat alarm. Why don't you take it and get it scanned for trouble codes...save you alot of guessing.
 
well, I appreciate the post, but according to the owners manual, its the overheat alarm, there is no low fuel pressure, poor fuel pressure alarm, just oil level and temp.
 
Please post the year and SN so it can be researched. Two strokes use a thermal NO switch that closes as the engine reaches overheat temp. I'm not sure if a 4 stroke uses the same switch...maybe someone can chime in here on that issue.
 
yes #21 was replaced with a quicksilver part, impeller was intact, yet one fin was pointed in the opposite direction, and there were cracks at the base, t-stat had normal corrosion for 11 years, no wires are pinching, finger trace on edge wires reveal no defects!
 
Have the valves ever been adjusted on this engine? I'm running out of ideas here. Run it in salt/brackish water? Flush it every trip?
 
If it was my truck I would be cleaning the throttle body throat and throttle plate...a film of grime can make a difference in how it idles and runs. Pull the water inlet screens and have a look into the cavity for mud or crud.
 
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