72 Merc 115

[liebe722000]

Hi all, i have a 72 merc 115 hp that friend says all is working cept the spring thing around distrubutor cap. Says it constantly lets gas in ? Problem ? It goes for awhile, like 30 seconds, then dies due to gas stops getting to carbs. Do i need a new spring thing ? Also what is the gas oil mix ? And is it ok for friend to rev VERY high in netural while checking. I said no cause you can blow a rod or piston ? Please advise. Thank You Mark Also friend says i put to much oil in last time. I put 1/2 quart to 6 gallons. When friend put midgrade gas in tank with no oil, it ran like crazy then died.

 

[WillyBWright]

Re: 72 Merc 115

1 pint of outboard 2-stroke oil to 6 gallons is correct. No oil was a very bad thing. I hope he didn't ruin it.

Try pumping the primer bulb to keep it going when it starts dieing. If it regains composure, you'll need to rebuild the fuel pump(s). Make sure the vent is open on the tank, and check for leaks in the line that might be letting air in. If gas leaks out, air will leak in.

 

[AMD Rules]

Re: 72 Merc 115

If you are serious about getting that motor running, you need to tell your friends to stay away. Take some time and read these forums before attempting to start it again.

There are many people who can help you get it running here, and you need to be aware that you can destroy that motor in < 5 minutes if a few simple precations aren't adhered to.

How long has in been since last run (before you got it)?

That motor need oil in the fuel.

Did you have it hooked up to cooling water when you ran it?

 

[studlymandingo]

Re: 72 Merc 115

When running on muffs NEVER rev the engine! Water must enter the engine at ALL TIMES it is running.

Always mix oil with the gas!​

 

[liebe722000]

Re: 72 Merc 115

I guess i meant to say that the spring thing around distributor cap, thats responsible for letting fuel in is not working. Can it be adjusted ? My friend only ran it for 20 minuets on pure midgrade gas, but guess its not destroyed. Mark

 

[WillyBWright]

Re: 72 Merc 115

That means it ran twenty minutes without lubrication. I can't imagine any motor could run that long without oil and not be ruined.

The distributor has nothing to do with fuel, only spark. The distributor cap has the sparkplug wires coming out of it. You must mean something else. There is a band around the distributor cap that holds it to the base.

Before we go any further, we need to make sure we aren't beating a dead horse. You need to do a compression test to see if the pistons survived twenty minutes without oil. What happens is some of the aluminum from the piston skirts welds to the steel cylinders. Now that it's getting lubrication, the pistons are able to move, but when it gets warm the aluminum on the cylinder walls swells against the pistons and the motor tightens-up until it cools down again. Then you start the process all over. That's what it sounds like is happening here.

Are you sure this guy is truly a "friend"? Sounds to me more like he's jealous of your owning a boat and is doing everything he can to destroy it for you.

 

[tashasdaddy]

Re: 72 Merc 115

sounds to me like you need to get a manual, and make it your best friend,

 

[Clams Canino]

Re: 72 Merc 115

Agreed. You need DISREGARD anything your friends told you - get a manual - and check it out. Or it's gonna be spare parts soon.

There is a timing and synch procedure dor the distributor and carbs. And if it sat a long time you need to clean the carbs 1st. This isn't gonna be "quick and easy" - not without killing it.

-W

 

[pman7]

Re: 72 Merc 115

When your "friend" put pure gas in your tank without oil was he adding it to some volume of your oil/gas mixture already in the tank or did he put that in your empty tank and run it on pure gas? The way you stated it I don't believe it's clear what actually occurred.

 

[Windykid]

Re: 72 Merc 115

As they said, do a compression test and let us know what you get.


Ran it for 20 minutes on strait gas