1987 Mecury Classic 50 No fire?

[NGABaldEagle]

I removed and cleaned the carbs and she ran much better. Starts with just a bump of the key.

Well after sitting a day....it wont start.
I ran it completely out of fuel and it wont start.
Turns over but seems to have no spark.

How do I isolate this issue?

Oh! turns over very fast.

 

[Plainsman]

Re: 1987 Mecury Classic 50 No fire?

Are you sure there's no spark?

 

[NGABaldEagle]

Re: 1987 Mecury Classic 50 No fire?

No not sure of anything.
Point is I dont know how to test.

I can learn though.
I removed both carbs and cleaned them.
I reinstalled them and motor idled good but maybe high.
I removed the tilt tube and cleaned.
I reinstalled it and its ready for the new steering assembly. New things for me.

I have a multi meter but dont know exactly what to do to check this motor. Im off on Friday 04-06-07 and will be trying to repair it.
ANY HELP WILL BE GREATLY APPRECIATED!!!!!

 

[Don S]

Re: 1987 Mecury Classic 50 No fire?

You need an OEM service manual. That is what the pro's use. Very few people can keep all the info in their head for every motor over the years.
That is why the Manufacturers make manuals with detailed troubleshooting info.
Maybe not the best for DIYers, but great info for the marine tech.


NOTE: The aftermarket Clymers and Seloc manuals contain only part of the info in the OEM manuals, and some of it is usually in error.

 

[NGABaldEagle]

Re: 1987 Mecury Classic 50 No fire?

I ordered a new OEM manual and a starter solenoid from Larry at Ellisport marine.
I dont think the starter solenoid is the problem but I have an issue with the one installed.
One of the posts on it is weak and crossthreaded.

My new steering should be here to day.
I should have it installed by 2pm.
If I wasnt having this starting problem I would take it to the lake today to test run.

Funny how things happen like this.

I was thinking last night that I could go out and remove a plug and turn the engine over.
I should see spark on the business end of the plug.

If I didnt what would I replace if no spark?

Coil?

 

[Plainsman]

Re: 1987 Mecury Classic 50 No fire?

You can get a spark tester at any auto store for about 10 bucks. I have the inline type where you just unplug the plug wire and the inline tester connects to the plug and plug wire.

 

[rivrrunner]

Re: 1987 Mecury Classic 50 No fire?

If you ran it completely out of fuel, did you reprime your line? Don't mean to be insulting, just remember spending a couple frustrating hours of my own chasing a "no spark" problem that turned out to be a "no fuel" problem because it had vapor locked.

 

[NGABaldEagle]

Re: 1987 Mecury Classic 50 No fire?

I didnt think of the vapor lock issue.

Here is where I am.

removed and cleaned both carbs jets and all.
Installed fuel pressure gauge in line.
Looks ok I guess and pumping bulb will get it hard with very slow bleed.
Fuel pressurewhen trying to start is around 2 psi.
Spark is good at the wires.

Plugs appear to not get wet which makes me thing no fuel is getting in.


I loosened the nut at the bottom of the bowl on one of the carbs and pumped the primer bulb to bleed gasfrom the bowl.
Pumped it up several time to get gas to flow through.
It does flow through and the anti siphon valvein the fule pump does seem to stop the back flow but fuel will go in the direction it is supposed to.

I am at my wits end.
What do I do now?

 

[NGABaldEagle]

Re: 1987 Mecury Classic 50 No fire?

Well, Rather than confirm to my wife that Im the local idiot, I asked for her help so I could spray the deadly starting fluid while she turned the key.

Fired right up.

VAPOR LOCK WAS THE CULPRIT.

I was within a few hours of backing it off the trailer with the plug in my hand.

Taking it to the lake on Monday.

Thanks fellers.