'79 85HP Johnson starting problem

[asdasc]

Apparently, I have become the go to guy on outboards among my friends now that I got my motor running. Oh well, it is fun and interesting. With your help I will try to perpetuate the myth that I know what I am doing!

My friends '79 85HP won't start without ether. We have tried choking it, priming it, etc with no luck. Give it one small squirt of ether and it starts right up and runs fine. Any ideas?

He got it recently and we have little history of the engine, but it does run pretty good once you get it started. If you shut it down and try it immediatly you can sometimes get it started. If it sits more than a minute or two, you have to resort to the ether.

By the way, since then, you guys have tought me the evils of ether in a 2 stroke, so we need to figure out a better way!

Thanks,

 

[asdasc]

Re: '79 85HP Johnson starting problem

By the way, I looked at the carb drawings on shop.evinrude.com and was confused. It doesn't show any needle valves or anything. There is just one orifice (part 6 in the drawings). Is that right?

 

[tashasdaddy]

Re: '79 85HP Johnson starting problem

are the choke plates working, closing all the way... it has throttle closest to back and choke front, butterfly plates.

NEVER put anything into a 2 stroke carb, other than premixed fuel, ( or if decarbing seafoam).

diagrams http://shop2.evinrude.com/ext/index.aspx?s1=bf6ad09c53cead335fcfd8a6471c0f7f

show #6 as the fixed low speed jet, and #32 as the fixed high speed jet. on carb serves the port side, the other the starboard side of the head.

have you tired a different fuel hose, tank to motor? to see if bulb is faulty.

http://forums.iboats.com/showthread.php?t=244013

 

[asdasc]

Re: '79 85HP Johnson starting problem

Thanks. I just realized that the carb you used in the FAQ is exactly like carbs he has! Also, since most of the cleaning of the carb involves just cleaning the orifices, and you can get them out without pulling the carbs (it seems), can I get away with simply doing that and not rebuilding the carbs? I need to have him take a look at the engine to see if you can get at those orifices without removing the carbs. The engine is currently an hour away from me so I can't check right now.

I was thinking about the fuel line also, that will be a good thing to check. It does seem to pump up pretty solid, though. I am pretty sure that he replaced the fuel line right after he bought it, but it is worth double checking.

Thanks for the help.

 

[tashasdaddy]

Re: '79 85HP Johnson starting problem

pull the carbs, and break them down, and soak them the are fuel passages in the inside that get varnished up. kit is a must or you waste your time.

 

[ezeke]

Re: '79 85HP Johnson starting problem

You cannot effectively clean and renovate the two barrel carburetors used on the 1979 V4 without removing them and installing new kits.

However, the fact that the motor runs well once started would make me wonder why you would want to rebuild the carburetors.

The symptoms that you describe demonstrate that the choke plates are not fully closing to allow the fuel to be enriched for a cold start (which is why starting fluid causes it to fire up).

If the choke plates do not fully 100% close and stay closed against the vacuum created by the pistons, the engine will continue to be difficult to cold start, no matter how many times you clean the carburetors. You can only tell if the choke plates are functioning properly by actual observation with the cover off, while someone cranks the engine.

They need to be perfectly synchronized. Once that is done, move the solenoid body in small increments until the plates fully close.

 

[asdasc]

Re: '79 85HP Johnson starting problem

Good points are being made, and I appreciate the help very much. I think I need to take a closer look at it again and see what I can figure out. I was pretty sure that we tried choking it by covering the intakes with our hands and it didn't help, but I could be wrong.

Thanks again, I will let you know what I find out and report back.

 

[wildmaninal]

Re: '79 85HP Johnson starting problem

I basically have the same motor as your friend. Make sure you have good compression, anything over 100 should be alright on all cylinders.

If the compression is good, then as the guys said, do a carb rebuild. I would also like to mention once you do a carb rebuild and you've done a link and sync on the carbs and still have problems you may want to check the fuel pump.

 

[asdasc]

Re: '79 85HP Johnson starting problem

Thanks, there was evidence that the previous owner was having fuel pump issues, we found a box with an old fuel pump in the boat, and the one on the engine looked like it had been replaced with a used one. This fuel pump can be rebuilt like in the FAQ, right?

 

[ezeke]

Re: '79 85HP Johnson starting problem

Quote: "I was pretty sure that we tried choking it by covering the intakes with our hands and it didn't help, but I could be wrong."

If you had the air silencer off the carburetors and were actually blocking the air on the face of both carburetors, you would be right.

 

[fdmsiv]

Re: '79 85HP Johnson starting problem

This fuel pump can be rebuilt like in the FAQ, right?

No, and I just found this out myself. I went out and bought a rebuild kit and then realized the fuel pump cannot be disassembled. I had to use 2 of the "wagon wheel" gaskets to make sure there was a good seal between the circular part with the screen and the pump housing. Check that all of the fuel hose is in good shape and tightly connected. Double check the tube from the fuel pump to just under the power head.

Make sure you can pump the bulb until it is hard, this lets you know that the carb floats are working correctly. Once the bulb is hard, make sure there is no fuel leaking at the connections.

 

[asdasc]

Re: '79 85HP Johnson starting problem

OK, it is boating season again, and so my friend is working on it. He rebuilt both the carbs, and did a great job with it, but have the same results. In reading another post recently, we found out about pushing in the starter switch to 'prime' the carbs. His switch does push in, but we can't see that it does anything.

How does the primer function work? Is there a solenoid or something that gets activated? Does the '79 85HP engine even have this feature?

Thanks,

 

[ezeke]

Re: '79 85HP Johnson starting problem

No it does not have a primer solenoid. It has chokes plates in the carburetors.

They are supposed to close when the key is pushed in, cutting off the air and forcing the engine to pull a richer fuel air mixture through the carburetors for a quick cold start. When the engine is cold you need to push the key in while you crank; pushing it before cranking does absolutely nothing on yor motor except flap the choke plates.

The choke plates need to close absolutely 100% and stay closed while you crank for cold starting; you need to verify that they are doing that by removing the front cover and watching the plates.

 

[asdasc]

Re: '79 85HP Johnson starting problem

OK, thank you very much. We will check this out.

 

[asdasc]

Re: '79 85HP Johnson starting problem

Just a quick note to thank everyone. You were right. In the end it was the choke plates not closing fully. Once we get them sorted out properly, the thing starts and runs GREAT!

Thanks again.