Stumped

[splitshot]

i have a 1977 200 evinrude i'm trying to get to run good, problem is when its cold the only way to get it to start is to spray pre mixed fuel down the carb throat...and when its warn if you let it sit for 10 minutes or more the same thing happens...what could this be?? i'm getting the correct spark, i pulled the fuel pumps the diaphrams are good, carbs were clean no trash..it seems like something is loosing prime but it will spin for ever and not crank until you spray a shot down the throat any ideas ?? i have also done a compression test and they are all within 2-3 psi of 95 psi..the electric choke works good too....once you get it going it idles good and if you switch it off and crank it right back up it cranks just as it should thanks Jason

 

[ezeke]

Re: Stumped

Take the cover off the carburetors and watch the choke plates when you crank the cold engine; they need to be 100% absolutely closed until the engine fires.

If they are not closed and/or won't stay closed while cranking, move the choke solenoid in small increments until they do stay closed.

The chokes enrich the fuel mix for the cold start by blocking the air, thus forcing the vacuum created by the pistons to pull more fuel.

When you use a spray pre-mix, you are just doing what chokes are designed to do when they are functioning properly.

 

[splitshot]

Re: Stumped

the cover is off and the choke is closing 100% and after you spin it for a couple of seconds and the choke opens back up you can see some of the extra fuel in the carb opening...but still wont crank until you manually open the butterflies on the carbs and spray down the throats...the carb bowls have fuel in them also...i have tried with the warm up lever down up and the middle with no help at all

 

[ezeke]

Re: Stumped

That is the point, you don't want the chokes to open back up until the engine fires unless you release them. You have choke plates on the middle and lower carburetors, correct?

When you cold start, you want the warm up lever fully raised at first to advance the timing. That and enriching the fuel should get you started as long as the battery is fully charged and cranking at 300 RPM.

 

[splitshot]

Re: Stumped

Yes, i have held them down for about 6 seconds at a time i figured any longer it would flood ? I will try this method tomorrow, it is a new battery and it is fully charged

 

[ezeke]

Re: Stumped

Try keeping them closed until it fires.

The float bowls are just reservoirs for the engine. The fuel is pumped into them until the floats rise and stop them from overfilling.

When you crank the engine, the vacuum created by the pistons pulls the fuel out of the bowls along with air, through the carburetors and into the engine.

When the engine is cold, the normal mix of air and fuel is not rich enough to fire, so closing the chokes enriches the mix.