Engine is back firing.(out exhaust)

[buckeye700179]

I have a 90hp evinrude outboard it cranks over but will not start all it is doing is back firing thru the exhaust at times it acts like it wants to start but it does not start.Number 2 cylinder is not firing, all others are. the mfrs serial number is EO6908 if you can I would like to know where the timing marks are located and also the firing order,Iam not sure what it could be, to becausing it to do that.if you could please let me know as soon as possible if you can.<br /> Thank You very much............

 

[Joe Reeves]

Re: Engine is back firing.(out exhaust)

I suspect that someone has had the flywheel off and did not torque the flywheel nut when installing it, resulting in a sheared flywheel key (throws engine out of time).<br /><br />If so, clean the flywheel and crankshaft tapers, install a new flywheel key, then torque the nut to exactly 105 foot pounds.

 

[buckeye700179]

Re: Engine is back firing.(out exhaust)

we did that and is still back fires and will not run. anthing else that you might know to try?

 

[Joe Reeves]

Re: Engine is back firing.(out exhaust)

I assumed that the engine was a later model 90hp. YOu did not list the year. If it is one of the older (late 1960s) with a belt driven distributor, then I'd say that you have the belt installed wrong which would throw the engine out of time. What year is it?

 

[buckeye700179]

Re: Engine is back firing.(out exhaust)

here is the info that i could find on the freeze plug100883b 100-s another one that i found is e06908 thanhs for the help

 

[StarTekh]

Re: Engine is back firing.(out exhaust)

chk your electrial stator down .. jon..

 

[buckeye700179]

Re: Engine is back firing.(out exhaust)

ok i'm new at this so i do i check this?

 

[Joe Reeves]

Re: Engine is back firing.(out exhaust)

Your engine is a 1968 100hp Evinrude. See your service manual about timing.

 

[buckeye700179]

Re: Engine is back firing.(out exhaust)

ok, so do you know where i can get a service manuel for this motor. thanks

 

[buckeye700179]

Re: Engine is back firing.(out exhaust)

ok, the motor is a 1968 100hp evinrude.i do believe that my trouble might be ingnition is there anyone that has book on this motor that has a fax machine or a scanner to copy the wiring diagram and send it to me via e-mail if so please send it to buckeye700179@yahoo.com or fax it to (937)435-2810 diagram of the wiring in the motor compartment would also be helpful. thanks roger