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Mariner 125 2 stroke stalls after 3mins unless primed....

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ojbruce

New member
Hi guys,

I have a mariner 125 2 stroke that runs fine for around 3 mins then stalls. The only way to prevent the stall is to pump the primer bulb. I have replaced the fuel pump diaphragm and checked the fuel lines, tried different primers etc.
Seems to do it idling, low or high revs.
Any other suggestions? Reaching the end of my tether (and bank balance)

Cheers guys, would really appreciate any ideas!
 
It sounds like it runs out of fuel. Have you run it w/a different tank? Did you notice if the primer bulb goes flat when it dies? That would indicate that the vent on the fuel tank is blocked. Run it w/the fuel cap slightly loose to see if it still stalls.
 
Thanks for the response, have tried it with other tanks and primer bulbs - I think the problem must be after the fuel pump as I have checked / replaced all the things before tha and also put a new diaphragm in the pump itself. Any other thoughts?

Cheers,
olly
 
runs fine for around 3 mins then stalls. The only way to prevent the stall is to pump the primer bulb.
Click to expand...
1. Does it always behave in that manner?
2. Will it start up immediately and then repeat the same all day long every 3 minutes?
3. Could it be that the tethered kill switch is faulty?
4. Could it be the mercury tilt limit switch is faulty?
 
Hi guy, thanks for the pointers.

1. When I run it on the water runs intermittently but will always stall unless I keep priming it with the bulb. 3 mins seems to be the time I get when I'm running it in the tank but when in the water it can go for longer - seems to depend on what revs I'm running it at.

2. It always starts but can take a while to start, probably because I have flooded it to try and keep it running

3. I don't think it's a kill switch issue as it doesn't cut out immediately

4. I don't think it's a tilt switch as it will do it even in the tank.

As you rightly pointed out, it sounds like its running out of fuel and when it begins to stall, if I increase the revs it will keep going for a little longer (maybe because it's pulling more fuel through?) but will always stall eventually. Is there something downstream of the fuel pump that could be obstructing the flow?


Thanks for all your help.

Olly
 
...something downstream of the fuel pump...
Click to expand...
Fuel filter. You may have a crack in a fuel line allowing it to suck air. Do you see any fuel stains along the lines from drip leaks. No fuel leaking from a line anywhere when you pump the primer tight? Is the fuel tank connected to the engine directly or w/a quick connect to remove the line? Inspect all clamps and fittings. It sounds like air is being sucked into the fuel line somewhere or it is being restricted. What year is the engine? Have you been running ethanol fuel? It could be the squeeze primer connections or the fuel line is deteriorated internally causing it to narrow under suction from the pump.
 
so it turns out that there was an air leak - the previous mechanic said he'd checked all the lines but replaced them again and it now runs fine. what a waste of money. thanks for your help, really good to convince me to recheck all those things. first time its run well for four years!

cheers and all the best,

Olly
 
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