Mercury 500 ID Help Please

[i386]

It says "500" on the cowl cover.

It's a 4 cyl 50HP. It appears to have a single carb. It's got "thunderbolt ignition" with a timing belt. Anyone have a nutshell explanation of thunderbolt ignition (I'm more familiar with older magneto types).

S/N is 2861616

Need to know anything you can tell me about this one. What year is it? Electric Shift? Is it a Model 500? The only numbers I see stamped is the S/N.

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extra bla bla bla...

It seems to be seized but maybe it's just because it's been sitting up for a while. We'll let it sit for a few days with a little oil in the cyls and see if it breaks loose. If the compression is good we'll probably get a manual for it and see if we can get it running. Otherwise it'll be used for parts.

 

[tashasdaddy]

Re: Mercury 500 ID Help Please

looks, like a 1969. http://www.maxrules.com/Merc_model_files/40-50.html go to maxrules.com and technical assistance you can get a manual at maxrules.com or oldmercs.com

 

[i386]

Re: Mercury 500 ID Help Please

Thanks, I think I found it here like you said:

http://www.oldmercs.com/197073Merc500.htm

If I'm reading that right, by the s/n it's a 1970. But on the front of the cowl cover it says "Kiekhaefer Mercury". Would you agree?

 

[tmcalavy]

Re: Mercury 500 ID Help Please

What's the second color on the cowl besides black...red or blue? Red band Mercs went to about 1970 I believe, after that (like my old 73 Merc 500) they were blue bands. My 73 had two carbs, each one fed two cylinders...if you only have one, something is missing. Should be a manual shift, using one lever control box. The model number should be on a metal tag/plate between the transom clamp screws.

 

[i386]

Re: Mercury 500 ID Help Please

I should have mentioned it was red before. I did notice that and it struck me a bit odd. I'm not 100% sure about the number of carbs it has so just disregard that for now. It looks to be a bit more chocked full-o-nuts than my old Chrysler and Evinrude engines so I'm probably lacking a bit in the parts identification department. If it's a '70 it hasn't been used much because it looks pretty good for the most part.

 

[OldMercsRule]

Re: Mercury 500 ID Help Please

I should have mentioned it was red before. I did notice that and it struck me a bit odd. I'm not 100% sure about the number of carbs it has so just disregard that for now. It looks to be a bit more chocked full-o-nuts than my old Chrysler and Evinrude engines so I'm probably lacking a bit in the parts identification department. If it's a '70 it hasn't been used much because it looks pretty good for the most part.

Those were some of the better if not the best old boat anchors: i386!!! The serial number is on the motor clamp on an aluminum plate between the hold down screws, (as you may already know). You can confirm the number as it it stamped on the flange extending from the block where the starter bolts up on the starboard side. The 1970 model was a sweet motor. The "thunderbolt" was a very reliable ignition at that stage. A cdi box is in front of the carbs, single coil, distributer and a trigger, (not points as the earlier models 1967 and back had, which were a pain, IMHO). The 1968 to at least 1971 were red bands, (the 72 may have been too). My motors, (inline6s) are bigger then yours, and that vintage were known as "silver blocks", I think the blocks were black starting in 1973 when the cowling bands turned blue. The things to ponder after confirming even compression: Fuel pump diaphrams, (easy to change), filters on the top of the two carbs, (a little more of a pain, but change if you don't know the status), water pump, (you need to drop the lu to change that), n' gear oil, (open both the vent and drain an fill from the bottom), check the surface gap plugs (NGK are cornsidered the best, Champions are good too). I would also decarb the motor, and I would fire it up prior to working on it, (make sure the tell tale pees when running it). If the carbs leak, you need to attend to that as well. Hope that helps, Good luck n' have fun. JR

 

[pm5471]

Re: Mercury 500 ID Help Please

I just came on the web site to ask what year my engine was and hear is the same engine as i have. My engine has the blue band and the serial # is 3350143. I need the year also. My next question is i got it running after it sat for a year and i put that thing with the garden hose on the water inlet and ran it for about a min. or less and no water is pissing out the small hole so i shut it down. The guy i got it from told me he replased some water tube in the lower end to fix that problem a year ago. Now what do i do? I don't have a manual or a book to help me.

thanks for any help
pete

 

[TriadSteeler]

Re: Mercury 500 ID Help Please

PM,

Your engine is a '72.

I had the same issue. If you are running at idle the pee stream will be weak using the muffs (That garden hose thingy) . I shut mine down as well. Then after getting some advice here, restarted it and put my hand on the water jacket (flat area on rear port side of engine behind the throttle linkage.) If after a minute, that area is too hot to touch, then you aren't getting water flow. It takes a few minutes for water to circulate. I let it idle for a few minutes and then bumped the rpm's up a little and got flow coming out of the tell-tale. Also, You will get better flow out of the tell-tale if your engine is in a barrel instead of running on the muffs. The water coming thru the hose very often doesn't keep up with the water pump.

However, in your case, I would change at least the impeller, if not the whole water pump anyhow before you run it again. That is something that should be done bi-annually, if not annually and EVERTIME you don't know the engine well or it has been sitting dormant for a while.

 

[i386]

Re: Mercury 500 ID Help Please

Those were some of the better if not the best old boat anchors: i386!!! The serial number is on the motor clamp on an aluminum plate between the hold down screws, (as you may already know). You can confirm the number as it it stamped on the flange extending from the block where the starter bolts up on the starboard side. The 1970 model was a sweet motor. The "thunderbolt" was a very reliable ignition at that stage. A cdi box is in front of the carbs, single coil, distributer and a trigger, (not points as the earlier models 1967 and back had, which were a pain, IMHO). The 1968 to at least 1971 were red bands, (the 72 may have been too). My motors, (inline6s) are bigger then yours, and that vintage were known as "silver blocks", I think the blocks were black starting in 1973 when the cowling bands turned blue. The things to ponder after confirming even compression: Fuel pump diaphrams, (easy to change), filters on the top of the two carbs, (a little more of a pain, but change if you don't know the status), water pump, (you need to drop the lu to change that), n' gear oil, (open both the vent and drain an fill from the bottom), check the surface gap plugs (NGK are cornsidered the best, Champions are good too). I would also decarb the motor, and I would fire it up prior to working on it, (make sure the tell tale pees when running it). If the carbs leak, you need to attend to that as well. Hope that helps, Good luck n' have fun. JR

Thanks! This one was given to me by a guy at work. It's too big to fit on either of my 2 boats so I gave it to my stepdad. The flywheel won't budge so it's either seized up or in gear. I would think if it's in gear it would move a little. I told my stepdad to put a little oil in all four cylinders and let it sit for a few days to see if it'll loosen up. If it makes it that far, a compression check will be in order. I was surprised to see it locked up like that based on the info I got from the previous owner. It was running, quit, and then just wouldn't start up again is what he said. No mention of seizure. It would be a shame if it had broken rings or some other terminal illness. Besides the corrosion of some of the wiring, the rest of it looks really nice. Over all it's really hard to believe it's a 1970 model engine. I'll let you know how it turns out.

 

[OldMercsRule]

Re: Mercury 500 ID Help Please

Hey i386, If it is locked up solid that does not sound good. I agree: it would move some (if just stuck in gear). It is not worth cracking the block open IMHO, as those vintage motors are fairly cheap, (at least here on the Northern left coast): running and in fairly good condition, (only needing the attention I mentioned in my first post). I does amaze me they last so long with a little care from time to time. JR

 

[pm5471]

Re: Mercury 500 ID Help Please

I can't figure out where to get a waterpump or the kit. I need some one to help me with the correct parts please. Feel kind of dumb becouse i can't find the correct parts in the catalog posted above .

thanks
pete

 

[fishmonger.33]

Re: Mercury 500 ID Help Please

i have one of these motors, i also believe the older ones are the best, i also had water pump problems, the previous owners just ran it anyways, and all the veins of the impeller became lodged throughout the entire system, it took a fair bit of work to clear out all the lines, but now it is good and running, other then a shifting problem which i am currently fixing, considering it is over 30 years old, i am impressed. lol other then that, best motor ive ever owned

best of luck to you

fishmonger