85 hp force needs help

[CEVANS097]

Hi everyone.<br />I have a 85hp force that i bought.The model # is 856X5L.Serial # 2791. When i start it up it seems as if it is running on 1 cylinder.I have cleaned all 3 carbs twice,I have checked the fire at all 3 plugs.Seems to be firing great.But when i start it up ,I can take the top plug wire off and the bottom plug wire off at the same time and it will not change how it runs.I can cover the top carb with my hand trying to choke it out,but it does not change how it runs.I can do the same at the bottom carb and it does the same thing.And when it is running it will back fire real loud and cut off.And when i am trying to crank it,it will back fire real loud.I have taken the flywheel off to see if it had sheard the key off,and gotten out of time.But it was where it is supposed to be.I have checked reed valves they are in good shape.<br /><br />Can someone please help!!

 

[JB]

Re: 85 hp force needs help

Are the spark plug wires to #1 and #3 switched?

 

[CEVANS097]

Re: 85 hp force needs help

If I switch the wires it will not make a difference.. Oh by the way i have checked the compression on all 3 cylinders and they have 140 on all 3 cylinders

 

[eurolarva]

Re: 85 hp force needs help

Is the backfire out the exhaust or the carburator?

 

[CEVANS097]

Re: 85 hp force needs help

The backfire is out of the exhaust..Oh..and I was wrong if i put the top plug wire on the bottom it will not run.

 

[eurolarva]

Re: 85 hp force needs help

So you have never run this motor before without this problem? Has motor ever run good since you have owned it? If so what have you done to it since the problem started?<br /><br />All issues that can create an exhaust back fire are related to timing. Cracked spark plug insulator, Improper timing or crossed spark plug wires <br /><br />My guess is that you have crossed wires somehow. Even though it runs with just number 2 plugged in my guess is that 2 belongs to 1 or 3 and the other ones need to go somewhere. You are going to have to find out the firing order of your motor and find a way to determine which plug goes to which wire.

 

[CEVANS097]

Re: 85 hp force needs help

I bought this boat a week ago..The ladie knows nothing about the boat.and as far as firing order,there are only 9 different ways the wires can go and i have tried all 9 of them.

 

[MWBROWN]

Re: 85 hp force needs help

In my 1984 85 hp book, firing order is 123. I cannot see a picture. Also says Champion plug number L18V. <br />I would get new plugs, unless you already have, to eliminate that problem.<br />Hope this helps some.<br /><br />Mike

 

[CEVANS097]

Re: 85 hp force needs help

Thanx for the firing order.I went yesterday to get new plugs,even though the plugs in it looked brand new.And the plugs that were in it was NKG BUHX,and that was what the book called for.Still runs on what sounds like 1 cylinder.

 

[CEVANS097]

Re: 85 hp force needs help

OOPS ment to say NGK plugs.