1992 90hp Johnson - wont start

[Bozol]

New fuel pump, new spark plugs, new coils, battery is fine, starter while not perfect is good enough to start the engine (turns over fine and fast), carbs were checked by a mechanic, says they are fine - didn't adjust. Getting plenty of spark at all four plugs. But, motor won't start. It'll go a bit if there is some ether sprayed in there but I don't want to make that a habbit.

Mechanic friend says he figures its fuel problem. Others have suggested timing but the engine was going in the driveway (water hook up) fine (after it took a long time to start) just a two weeks ago and hasn't been on the water for a bout 3 weeks - could the timing go screwy in that short time? What else could it be?

Any suggestions? Does this sound un-fixable? It is cold here, -3`C this morning. Usually warms up to about 8 or so during the day (Inuvik, NWT, Canada). Still a few weeks of season left before freezeup!

Any help very appreciated,

Cheers,

Bozol

 

[bgbass.1]

Re: 1992 90hp Johnson - wont start

if it runs a little with ether its a fuel problem.i would check fuel for either water or old gas. then check carb. to make sure you getting gas if not could be a pluged line

 

[Dhadley]

Re: 1992 90hp Johnson - wont start

Yep, a fuel delivery issue. As long as it's getting spark at the right time. We can assume it is if it runs OK as long as you manually feed it fuel (no backfiring). I'd clean the carbs to start with.

Tell your "mechanic" that when you asked him to check the carbs you meant for him to do more than simply verify that there were indeed 2 carbs bolted on.

 

[Bozol]

Re: 1992 90hp Johnson - wont start

Nice one Dhadley!

I actually took the carbs off myself and brought them to the mechanic who had a good look. He felt they were fine and like I said, didn't adjust anything.

How much water in 1.5 gallons could cause a problem? I had the vent open on the tank the last couple of days and it has rained off and on. I never thought that was a problem, but perhaps?

If the fuel pump is ok, and the carbs look good, then what else could be blocking fuel to the pistons?

Cheers,

Bozol

 

[Bozol]

Re: 1992 90hp Johnson - wont start

Changed the gas - no difference
Changed the fuel pump back to the original - no difference
Changed the sparks back to the original - no difference. Either way the sparks smell like gas but aren't soaked.

Have some questions to help me out:

If the engine went for a couple seconds with ether could that indicate a spark issue? i.e. the lower flash point is getting the engine going but the spark isn't hot enough to ignite the fuel?

Could it be a vacuum problem? i.e not enough pressure coming out of the crank to push the fuel into the carbs properly? I checked the fuel coming out of the pump as the starter turns but have no idea how much should be coming out. I'd say about 20ml came out in roughly 5-10 seconds of turning. Is this normal? Too much / little?

Its a 4 cylinder so I'm at least expecting some coughing and sputtering but nothing happens at all. The bendix turns the fly around and around and around and nothing else happens. Still just a gas problem?

Any help is very appreciated,

Cheers,

Bozol

 

[CharlieB]

Re: 1992 90hp Johnson - wont start

Leave the fuel line off the carbs and pump the primer bulb, does fuel come out?

Look at the fuell line VERY carefully, you could have a small split or crack or bad seal in a coupling, any or all of the above will allow the fuell pump to suck AIR NOT FUEL, and the engine will not run.

 

[Bozol]

Re: 1992 90hp Johnson - wont start

Lots of gas comes out of the line before the carb hookup when the ball is pumped. As well, I've had two different fuel lines from two different tanks going as the original fuel pump (the one thats on now) is oil injection while the new pump is mixed.

Could it be the line from the contact point on the engine to the pump?

 

[Bozol]

Re: 1992 90hp Johnson - wont start

The coils on the motor are from an Evinrude 70hp. They look indentical in size and shape to the originals and fit perfectly, but perhaps they're not generating enough spark to ignite the gas?