77 85hp evenrude no start

[jfl909]

I bought this motor not running. It has 120-125 psi on all four cyc's. I have replaced the fuel pump, and rebuilt the carbs. It has good spark, but will not start. With the fuel line disconnected it has good fuel flow out of the pump, and the carbs are full of gas. when I pull the plugs out they look dry like they are not getting fuel. With a quick splash of carb cleaner it will fire up for 1/2 a second. I don't want to harm the motor so I have only tried it twice with very small amount. Does any one have any ideas? Does this motor have reed valved and could this be the problem?

 

[JB]

Re: 77 85hp evenrude no start

Top Secret file ^^^.

 

[emdsapmgr]

Re: 77 85hp evenrude no start

The compression is right on. If you put some premix fuel in a spray bottle you may be able to get the engine to fire/run while you spray that mix into the carb throats. If it fires/runs while doing that, the powerhead and reed valves are probably just fine. Your test with the carb cleaner pretty much verifies this already. If the engine has not run in some time, you may find some dried fuel (or even debris) in the upper carb body passages which is restricting fuel to the engine. A complete carb teardown and cleaning with an aerosol carb cleaner will easily fix that.

 

[jfl909]

Re: 77 85hp evenrude no start

I just finished cleaning the carbs and rebuilding with new carbs kits.

 

[ezeke]

Re: 77 85hp evenrude no start

The choke plates have to be 100% closed for a cold start on your engine and they need to stay 100% closed until the engine fires. You will need to take the cover off the carbs and watch while someone cranks the motor to be sure that this is happening. You can synchronize the choke plates with the linkage so that they work together precisely, then move the choke solenoid in small increments until it works correctly.

The throttle plates have to be closed at idle and perfectly horizontal at WOT. You will need to move the control arm through the range to establish that this is working correctly.

The engine must be cranked at 250 RPM minimum cranking speed for the ignition system to fire. This requires a fully-charged, powerful battery, immaculate connections and good cables.