strange problem with evinrude

[SeaSaw]

I have a 1973 85 hp Evinrude. Model# 85393M Serial # J0008608. I just purchased this motor a few weeks ago. It did not run. I rebuilt both carbs, taking time to clean every passage I could see, soaked them in chem dip and new rebuild kits. Spark is good on all cylinders. I rebuilt the fuel pump and installed a new water pump kit. gas in carbs had turned into taffy, but I feel I got it all out. the choke is working fine. if you squirt a small amount of fuel into the cylinders via the spark plug hole (new plugs too) it will start and run fine. after running until warm it will start again. if it cools off it will not start. the plugs remain dry. I took it out on the lake and ran 3/4 tank of fuel through it and at speed it runs perfect. It idles a little rough, like it is a little lean, but there is no adjustment. It sneezes back through the top carb every now and then (like a lean condition) but is too random to make me think there is a damaged reed valve. Is there something I am missing? I would like to think that I have a fair grasp of how this engine works, but maybe not. also a compression test showed 130 psi on all cylinders. Visual inspection of the reed valves (through the carb ports) was fine. If anyone has any sugestions it would be greatly appreciated.

 

[F_R]

Re: strange problem with evinrude

OK, that engine has a two stage choke solenoid. As built at the factory, one stage is activated through a thermal switch in the top of the cylinder block. That provides partial choking for warm-up. The other stage is activated by the choke switch up front. A lot of people rewire the system so that both stages are activated by the front choke switch.

Whatever, if both stages are not being activated, it won't choke with full pull on the plunger spring. Try "assisting" the chokes with a finger when you cold start it next time and see if that doesn't help. If so, figure out if you are activating both stages and/or if the spring is good.

 

[SeaSaw]

Re: strange problem with evinrude

Thank you for your reply. I dont know what you mean by 2 stage, however I did as you said and held the choke shut with my fingers and had a friend crank engine, it did start from completely cold. So the problem must be with the choke. with the carb cover off and key on, when I switch the choke (@control box) it appears that they are closed. If I understand what you are saying it has a means of opening the choke partialy for warm up. My problem must be in the second circuit. I have a Clymer manual and I dont see the second circuit. is it mechanical or electrical? Again, thank you for your swift answer.

 

[F_R]

Re: strange problem with evinrude

2 stage meaning thre are two windings or coils in that one solenoid can. One winding pulls the plunger down weekly for warm-up. Both of them at the same time slams it shut tight for cold starting.

This diagram is for the wrong motor, but the choke circuitry is the same. Bottom line is you need 12 volts at BOTH wires going into the solenoid when cold cranking.
http://i155.photobucket.com/albums/...g197285hpSelectricfrverified.jpg?t=1178240110

 

[SeaSaw]

Re: strange problem with evinrude

thank you for your reply. I understand now and I will check tommorrow. At the very worst I can use the manual choke lever for cold starts if I have too. thank you again you have been a great help.