Cold start on 40 Merc

[wisernow]

i have a lot of difficulty starting the 40 Merc on the first crank. Quite frequently, I have to use starter fluid. After it is warmed up, it is not a problem to restart. I have had a tune up, plugs and carb rebuilt. Any thoughts.

 

[phatmanmike]

Re: Cold start on 40 Merc

if its a 2 stroke, stop using the starting fluid or youll end up with a expensive lawn ornament<br /><br />as far as it not starting imediatly... we need more info...<br /><br />is this every time? is it carb of efi<br />is it 2 or 4 stroke<br />what have you done to the motor?<br />what is the compression?<br />it could be a zillion things.....

 

[DHPMARINE]

Re: Cold start on 40 Merc

I'll guess the choke doesn't close really tight,or the fuel enrichment valve isn't working.<br />Please use carb cleaner to get it going,not so damaging.<br /><br />DHP

 

[wisernow]

Re: Cold start on 40 Merc

Thanks for the ideas. It has carbs, and yes, every time it has cooled off it is very difficult to start. It is a 1981 model with very low running hours. I have replaced the fuel pump, rebuilt carbs, new plugs. Where is the fuel enrichment valve?

 

[DHPMARINE]

Re: Cold start on 40 Merc

Not sure you have the valve,but it should have a black wire and yellow/black wire going to it.<br /><br />DHP

 

[Chinewalker]

Re: Cold start on 40 Merc

It just uses a simple choke. It operates off a solenoid. First, confirm that it's operating when you hit the choke button. Second, make sure there's no gap between the choke flapper and the mouth of the carb. Those older Mercs need LOTS of choke. <br /><br />Try this - stuff a rag in the carb next cold start and see if it kicks off any quicker. Obviously, don't hit the choke button while trying this. If it does kick off faster, then you've got a choke issue...<br /><br />- Scott

 

[WillyBWright]

Re: Cold start on 40 Merc

I had a customer with that motor. He purchased it new. He brought it to me for sarting problems in the late 90s. I found minor things here and there and gave it a tune up and for me it always started and ran great. For the next year he kept bringing it back for starting problems and It always worked great for me. I finally had him back his boat in and start it. He pumped up the primer bulb, raised the warm-up lever, pushed the choke button twice to set the automatic choke and cranked away.<br /><br />Now being the proud owner of one of these motors you see his mistake right away. There is no automatic choke to set. Push the button and it's choked. Let go and it's not. He'd been starting it that way since he bought it 15 years earlier and he was unhappy that nobody could ever fix the problem with the motor. He was happy as a clam once I showed him.<br /><br />I find on those motors that you have squeeze primer bulb it hard enough to make some gas leak from the carb. If the motor is tilted fully down it'll tend to run into the motor. Otherwise it drips out and does no good if the motor is trimmed really high. Then choke until it fires and try to let go before it floods. If you're not quick enough, retry without choking. You'll probablly have to tap the choke a few times to keep it running until it warms up a bit.