Mercury 500 not starting

[johnboywalt]

Hey I am absolutely new to baot motors, I bought a boat with a mercury 500, 50 hp motor. I completely rewired the wiring harness, so now the motor cranks and cranks and cranks, but never starts. I do notice some gas coming from somewhere around the bottom carb when I let off the starter switch. <br />Any help anyone could offer would be great, so my wife isn't right about the boat being a lemon.

 

[JB]

Re: Mercury 500 not starting

Go to Engine FAQs, John. "Outboard wont start".<br /><br />Good luck, and let us know what you find.

 

[johnboywalt]

Re: Mercury 500 not starting

Well nothing yet I have given up for the day, I think I will employ the help of my wife to make sure the sparks are there. I did take the carbs off and found the lower ones float to be stuck with some gunky stuff. I cleaned that up and it seems to be fine now. I am a little leary about my fuel/oil mixture though. I do think the spark is the best way to go, so thanks for that link.

 

[johnboywalt]

Re: Mercury 500 not starting

Oh yeah how exactly do I make syre the timing is correct? Same as a car, with a timing light? Also How do I adjust it? I know I should get a manual but I am a cheapskate. I know this thing has coil packs but I am not sure if the box with like ten little wire connected to it is some sort of distributor?

 

[joblo33]

Re: Mercury 500 not starting

no, the distributor is the pinkish thing attatched to the flywheel by a belt. Depending on the year it might or might not have one.

 

[2cycle]

Re: Mercury 500 not starting

The manual will more than pay for itself and will enable you to easily time the motor with instructions. If it is distributor ignition, it's not really that hard once you understand the overall system and follow the timing instructions.<br />Clymer seems to be a decent manual and I used it on my inline 6. Good luck,<br /><br /> "Sue Ellen"

 

[joblo33]

Re: Mercury 500 not starting

I personally like the Seloc for this motor. It's step by step and includes a picture for almost every step.<br />Eric

 

[johnboywalt]

Re: Mercury 500 not starting

I think that will be a wise choice on my part, I will probably get one this weekend to help me understand the motor a little better. Thanks.

 

[Greg New Zealand]

Re: Mercury 500 not starting

Originally posted by johnboywalt:<br /> ... I know this thing has coil packs but I am not sure if the box with like ten little wire connected to it is some sort of distributor?

What is the serial number? Need to check the year to find out what configuration you have - sounds like a 1976 model or later with 4 coils and switchbox.

 

[johnboywalt]

Re: Mercury 500 not starting

There is only one number I can find and it is on that box. There is actually 16 wires on that, it says 4cyl 2 stroke, p\n I will have to wait till I get home to post that. I put it in at one of the web sites that are linked to this page, it said the number I have falls into a 1971-76 if I remember correctly. The title says the boat is an 1980. Thanks though I will post that in a while.

 

[Motor Boater Bill]

Re: Mercury 500 not starting

Look for a plate on the outside of the motor, around the transom clamps or on the side of the leg, with the serial number stamped into it. It will have other info printed on it also.

 

[johnboywalt]

Re: Mercury 500 not starting

Ok, I found a serial number right between the clamps it is 4805721, I havent been able to verify what year it is yet I am still lookiing on the net. Any help would be appreciated. Oh yeah I am not getting a spark on any plug?

 

[johnboywalt]

Re: Mercury 500 not starting

Alright I found a general listing that number falls in the 1975 category. Any body confirm or deny that?

 

[joblo33]

Re: Mercury 500 not starting

1977<br /> http://maxrules.com/graphics/merc_pdf/merc_pages_23thru26.pdf <br />Eric

 

[johnboywalt]

Re: Mercury 500 not starting

Thanks<br /><br />Now I really need help though. I had no spark as I said so I started reading out wires. I had nothing going from the harness under the fly wheel to the switch box, so I took off the flywheel and the big magnetic thing which is part of the distributor system I guess, well after that I found a wire from underneath there that was completely disintigrated. But I can't repair it because I don't know how to get the distributor off. I know I need a manual but none of the boat shops I have looked at here have any for that old. I could use any help anyone wants to give thanks.

 

[Motor Boater Bill]

Re: Mercury 500 not starting

You can orger a manual at:<br /><br />www.oldmercs.com<br /><br />Rotten wires were apparently common on the mid-1970's Mercs.<br /><br />Is the wire gone or just the insulation? If you can see that the wire is there and just the insulation is gone, causing it to short out, you can try wrapping the wire and see if that gets spark happening. This is not a long term fix but may help in moving forward with diagnosing your problem. Be sure to check the wires to the kill switch and Mercury switch (if you have a Mercury switch) as if these are shorted they will prevent spark.<br /><br />Wiring diagrams can be found at:<br /><br />www.maxrules.com

 

[johnboywalt]

Re: Mercury 500 not starting

I don't know wether I have either I haven't noticed them. No the entire wire is gone it fell apart when I touched it. Odd I think the three next to it were fine. It is one coming from the trigger. I have my book and will be removing/fixing tomorrow hopefully. Thanks