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1990 40 HP Fuel troubleshooting

C

chucka

Contributing Member
"I had trouble tonight startin

"I had trouble tonight starting my 1990 40 hp with electric start. I had it running last weekend for the first time this season, when it started kind of hard, but it ran OK once it started. (I'm using fresh fuel in a clean tank.)

Tonight it started reluctantly after many cranks, then died within a few seconds. I found I could keep it running by pumping the ignition key (primer solenoid). It dies when I stop pumping the key. This leads me to think I'm not getting enough fuel.

I pulled the hose off the fuel pump outlet and there appears to be a pretty strong fuel flow when I crank the starter. (I'm not sure how much is enough.)

The Clymer book says to "check the primer solenoid by depressing the primer while running the engine at 2,000 rpm and looking for about a 1,000 rpm drop as the mix goes rich." But I can't keep the engine running well enough to tell anything. I think the solenoid is located on the starboad side of the engine, but am not 100% sure. It looks like there are 3 small hoses coming off the the fuel pump, one goes to each carburetor, the other seems to go to the primer solenoid and I had a hard time telling where from there. I'll check the resistance of the primer solenoid coil in the morning when I have some light to see what I'm doing. It's supposed to be 4-7 ohms between the purple/white lead and the black lead.

I would really appreciate if someone can provide additional troubleshooting advice or explain how the solenoid is supposed to work.

Striped bass are running in the bay and I'm anxious to get on the water.
Thanks!
Chuck"
 
"Chuck.... Look upon the fuel

"Chuck.... Look upon the fuel primer solenoid as if it were an electric choke. Pressing the key in sends 12 volts to that solenoid which opens the fuel passages within it allowing fuel to flow thru to the intake manifold area.

From what you've had to say, obviously the primer solenoid is acting exactly in the manner for which it was designed.

Your problem is that the carburetors are fouled, clogged, gummed due to sitting.... a common problem.

The cure is to remove the carburetors, clean and rebuild them using new complete carburetor kits.

Be sure to manually clean the brass fixed high speed jets that are located in the bottom center of the float chambers. Don't depend on the soaking cleaning solvent to do that job by itself."
 
Thanks Joe!

I'll try to

Thanks Joe!

I'll try to pick up the kits locally today and let you know how it works out.

Chuck
 
"Joe got it 100% right. I pic

"Joe got it 100% right. I picked up the rebuild kits today and cleaned out the bowls. The upper carb was gummed up with sticky orange goop - it reminded me of the color and consistency marmelade. I took some photos and will try to post them here soon for reference by others. The lower carb had grey/white almost powdery deposit, maybe it was an oxide of aluminum. I cleaned them up, replaced the floats and needle vales - this may not have been necessary but the kits available to me today included them and I figured if I was taking the carbs apart I might as well replace them. The repair went very well until a brief moment of lost confidence. After putting everything back together and trying to start-it, the engine cranked and cranked but would not fire.... until I realized that when I tested the fuel pump last night, I had pulled the kill switch to disable the ignintion. Oops! With the kill switch in place it started on the first crank. I adjusted the idle and it's now running great. I clocked 26+ knots on flat water with the GPS tonight. In a 13 foot Whaler, that feels like flying. I had a nice evening fishing on the Warren river until about 10:30 pm, a few bites, no stripers, but it beat the heck out of last night.

Thanks again Joe! This was my first time dissasembling a carburetor and I learned a bit. It did leave me with a few more questions, but I'll leave them until another time (maybe when I post the photos). It's late for me and I need some sleep.

Best regards,
Chuck"
 
"I got a private email based o

"I got a private email based on this post asking about shop manuals - Here is my reply

The manual I bought is a Clymer's Guide. They are pretty widely available. I think West Marine and Boater's world both carry them locally in their stores. You can also probably find them at major book chains and online at Amazon:
http://www.amazon.com/Evinrude-Johnson-Outboard-Shop-Manual/dp/0892875542

That said, if you can find the repair manual specific to your engine - I would recommend going with that. It should provide more details specific to your engine. The Clymer's book I bought covers 2 to 40 Hp for 1973 to 1990. As such, it doesn't devote a lot of detail to any specific model. It does inclde some general guidance, which may be lacking in the official manual for a specific engine model.

From my experience, these books are good for getting some general guidance, but do not provide step by step instructions for each procedure. They seem to be written for trained mechanics who are familiar with basic procedures or may have access to other supporting details.

As an example, one of the steps in dissassembling my carburetor just says "remove the high speed nozzle and gasket." There is no illustration pointing out exactly where the high speed nozzle is or identifying what is different about it from the "high speed orifice with fixed jet" mentioned in a previous steps. These are items that presumably a mechanic or a more experienced do-it-yourselfer would understand.

I also own a 26 foot Trojan Express Cruiser with a Chrysler LM 318 inboard, and I had issues with its Carter aluminum four barrel (AFB) carburetor a couple of years ago. The four-barrel seems much more complex than the Johnson outboard carb. At that time, I bought an aftermarket book about rebuilding the Carter AFB, read through it then decided to send the Chrysler carb out to a shop to get it re-built. The entire book was dedicated to rebuilding the carb. It gave me a better understanding of how the carb works, but I didn't feel confident enough to rebuild it myself. - and I consider myself to be a pretty handy person.

What gave me the confidence to do the outboard, was this post I saw on another board...
http://www.outboardmotor.biz/t/001324.html

starcraft guy wrote>
I have a 1960 40 hp flooding real bad, Would any have pic, of disassembly and assembly

fireman757 answered> You don't need a pic. Remove the carb and take out the four bolts holding the bowl on. Your float is probably stuck. Get a rebuild kit and replace the float, needle valve under the float and the seat that the needle valve sits in. All this can be done with a screwdriver (except carb removal). Set the float (by bending slightly the little "fin" that rests on the needle valve) so it is level with the carb when turned upside down. Make sure that you clean the high speed jet while you are in there. This is the long tube. Blow it out with compressed air or you might shoot a little WD40 or carb cleaner through it. This should get you back on the water in about two hours.

So I didn't worry too much about the finer details. I disassembled it, cleaned it thouroghly, replaced what was obvious, left the rest alone and it worked out OK for me.

Regards,
Chuck"
 
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