Purchased used Mercury 500

spamn

Seaman
Joined
Jul 19, 2010
Messages
57
I just purchased a used Mercury 500 50hp 3 cylinder for a pretty good price. The only problem is that I have no idea what condition it is in. I popped the cover and VISUALLY it looks clean and in good shape. It came with no controls or anything, but has tilt/trim.

I have a Mercury 402 40hp 2 cylinder on my boat. I was told that my controls will work with it and that I can just swap it over. Will the controls work? If so, my controls do not have anything for tilt/trim. Are there some seperate things I can purchase to work the tilt/trim?

Other than swapping the controls over and hooking up a battery and fuel, is there anything I can look at right now to get a good estimate of the engine condition?

If worst comes to worst, I am hoping I can use the tilt/trim and prop for my current engine and part out the rest of the 500.

Thanks in advance for any advice.
Sam
 

spamn

Seaman
Joined
Jul 19, 2010
Messages
57
Re: Purchased used Mercury 500

Also, I was able to find the year of my 402 from the serial number. I have searched many of the sites that list this information but cannot seem to find it for this 500. The serial number is 4965581. If anyone can provide me with the year or some general information about this engine, it would be appreciated as well. Assuming it's a 2 stroke with a 50:1 oil/gasoline ratio as well.
 

spamn

Seaman
Joined
Jul 19, 2010
Messages
57
Re: Purchased used Mercury 500

For whatever reason I had it in my mind that it was 3 cylinder. It's definatly a 4 cylinder. Not sure why I was typing that. That also solves the year problem. Appears to be a 1978 if I did that lookup correctly. The thing is very clean inside. Looks like it is only a few years old. Both carbs are spotless, all wiring is in excellent condition. Hopefully the powerhead and lower unit are as good as they appear. Also, from what I can find there wasn't a power tilt/trim on this engine in this year. Does that sound correct? There are definetely two vertical pistons on the transom mount. Sorry for my ignorance but I know nothing about this. I know that there should be controls and a motor and probably some other stuff but, I have no idea where to start or how to even see what works out of what I already have.
 
Joined
Sep 5, 2007
Messages
1,790
Re: Purchased used Mercury 500

In the archives here there are several very good post about 'waking up a sleeping outboard" and the things you need to check out before you try to start an engine is unknown condition.
 

hotrod53

Chief Petty Officer
Joined
Oct 16, 2009
Messages
508
Re: Purchased used Mercury 500

I have a '77 Merc 500 Thurderbolt, hadn't been run for 12 years. I started it today for the first time, runs like a champ.

Spray some fogging oil in the plug holes and roll it over by hand, check the carb bowls for crap, replace the water pump, mix the oil at 25:1 for the first time, check the plugs, fire it up!

The two vertical pistons are shocks, not lifts. That makes the engine go up and down smoother. They may have other functions as well, not sure.
 
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