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2007 Mercury 40HP difficult to pull cord - cannot start

C

cshiel

New member
Just brought a 2007 Mercury 40HP, 2 stroke, had it going last weekend but this weekend its exceedingly difficult to pull the starter cord. So difficult that I cannot start it.

Checks done:
  • Neutral - check!
  • Spark plugs out - turns easy.
  • Spark plugs back in - hard to turn.
  • Flywheel cover off - very hard to turn by hand.

I'm not sure if I doing something silly, I seem to be doing everything that I was doing last week.:confused:
 
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fastjeff said:
Please tell us you had oil in it when you last ran it!

Jeff
Click to expand...

Good point! I brought it second hand and assumed it was all good to go. Will try to top up oil and try again.

Second thought - don't think this is oil injection, seems to be mixed in with the fuel at 25:1 ratio.
 
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That model uses an oil pump, not pre-mix. If you ran it without oil, it's too late to save it. I hope not!

Jeff
 
Is there a transparent plastic tank attached to the power head? And a removable oil filler cap visible with the hood on?

Jeff
 
Most newer ones do, but some people remove the tank (and the oil pump) and go back to premixing.

Did you run premix through it, or just straight gas?

Jeff
 
My brother was able to start it twice but I have no idea what he did. He claims he followed the same procedure as me but I cannot get that cord out quickly enough to start it.

I took the spark plugs out and was able to crank it put them back in but same problem. I'm very confused.
 
fastjeff said:
Better look into electric starting.

Jeff
Click to expand...

I'm not a weak person, there is definitely some resistance that feels not natural. I can pull the cord out but not in one smooth movement.
I am a physically powerful in my arms although maybe a bit unfit, but I did not have this problem first day I purchased the motor so it can't be a question of strength.
 
Ok stop yanking it you are going to break something. Pull it out until it catches then yank you may need 2 hands to start it a 40 is not a small engine.
 
Have you checked the gearoil? How old is the impeller? If the impeller is more than two years old pull the gearbox and see if it turns over any easier? Change the impeller at least every other year, once yearly even better.
 
One of my customers has a 50 hp Yamaha with a racing head. It has so much compression I can't start it. He puts both hands on the starter handle and YANKS like crazy! (Why that puny recoil hasn't self-destructed by now is a mystery.)

It takes a STRONG pull.

Jeff
 
fastjeff said:
One of my customers has a 50 hp Yamaha with a racing head. It has so much compression I can't start it. He puts both hands on the starter handle and YANKS like crazy! (Why that puny recoil hasn't self-destructed by now is a mystery.)

It takes a STRONG pull.

Jeff
Click to expand...

Yeh but what I don't get it why its suddenly so difficult to start? I can crank it now - using all my strength but I'm beat after 5-10 goes.
 
Is this a new thing? When it dont start pull the plugs and see if they are wet? If wet do they burn with a lighter? Have you done a spark gap test? It should start on the first two pulls if everything is good. Maybe drain the float bowls in a dish and see if water got into the fuel system?
 
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