Core plug from carb in motor

[Dooley87]

My motor started running very bad the other day on the lake, took it home and was running it to see if I could diagnose the problem when I started hearing a sporadic ticking coming from the motor before it killed. Took the carb apart and found one of the small aluminum core plugs that fill the holes from the sand casting was missing. If it ended up in my motor do I have any hope? How should I go about getting at the plug inside the motor?

[Dooley87]

I started thinking about it and there's no way for a core plug to get from the carb's fuel bowl to inside the motor, searched the ground and sure enough there was the old plug, must have fell out when I took the carb apart, I put a spare plug back in from another rebuild kit I had but the motor still will not idle and stay running and will make a knocking or ticking sound here and there. The points are gapped properly, I have a new fuel pump on it, there aren't any leaks in any gas lines I can find, what could my problem be?

[delcecchi]

This is a situation where one of those fiber optic cameras, like the one Milwaukee makes, would be real handy. Pull plugs, and stick it in to take a look around. Or check compression at least.

What kind of motor?

[Dooley87]

1974 Johnson 25 25r74m I know enough about small engine repair to get me in trouble lol

[delcecchi]

Motor won't run, ticking sound, old simple motor, nothing fancy that an old guy can't understand.

Possible stuff that could be wrong, assuming it used to work in the not distant past.

Ignition. Aren't there points under the flywheel? Could be worn out or mis-adjusted. Flywheel is keyed to crank. Could key have sheared? are there magnets under there, glued down? If so could one have come loose.

Cylinder== could there be a broken ring or burned or otherwise broken Piston?

[Dooley87]

Yes used to run like a top. Cleaned and rebuilt carbs this spring along with gaping the points correctly, checked the points right away and they were still at .020. The rest are things I will add to the list to check. I haven't heard the ticking noise the last few times I've tried to run it though, it will start up idle very poor and rough, start to die, if I put the choke on it will run a few more seconds before dying, I've tried adjusting the slow speed needle and that isn't it. Just going to have to start a checklist of possible problems and test them one at a time I guess, I should get a gauge to test compression, I'm assuming it should be around 120

[Surface Tension]

Could be a number of things but do the compression test first.

Did you pull the spark plugs?

Could the ticking be an arc from the coils?

Since you had the flywheel off could you have moved a wire in such a way that its grounding out. Also the check the wires at the pivot point coming off the mag to coils for an open or short.

Does it run rough just at idle?

[Dooley87]

When I first noticed an issue I was running wot just fine, when I came up to the dock and idled down it would idle rough and kill. Then at home when testing it it would idle rough but if I ran it wide open it would be fine, now I can't get it to open up at all without it dying.

[Dooley87]

I checked the compression, top has 120 and bottom has 115 which is great. I re checked everything on the magneto and everything looks kosher there, I couldn't find any magnets on the flywheel so I'm unsure if there were any there originally or not, didn't find any loose ones anywhere, I took the "sending unit" out of the fuel tank and it isn't clogged, put on a new fuel hose and primer bulb, checked for spark and there's good spark. It starts and revs good then starts spitting and sputtering and dies, it will start again and almost instantly shut off and it started one last time and jerked and shut off, won't start again now and primer bulb is hard if I try to pump it so it has fuel, I'm lost. I have video of it running but can't upload it since I don't have any of the supported accounts for uploading videos

[delcecchi]

Acknowledging that I am not a mechanic, sounds like a carb problem to me. Or at least something with the fuel supply.

I have a story of something similar from many years ago. I had a 40 merc, like a 1984 2 cylinder 2stroke. It wouldn't run. Would start and then die. I was a ways from the cabin and had family along. Turned out if the bulb was kept squeezed, even though it was hard, the motor would run well enough to get home.

I decided the problem was that little bowl on the side of the motor, function unknown, that had a strainer in it. I took it off and cleaned it all out and stuff got better. There wasn't water in the bowl, but it must have been some sort of dirt clogging the screen, although it wasn't visible to any extent.

Moral? If you have one of those bowls, clean it out and the screen too. It might help.

[Dooley87]

No bowl but I know what your referring to, my grandpas 1983 Johnson 115 has one and I always referred to it as the fuel filter, since my motor is smaller my filter is right on the pump and I just installed a new pump thinking that might be the issue. After talking with a buddy at work he thinks its a clogged jet since it will run a little then die, even though I sprayed all the jets and ports out with carb cleaner, going to have to take another look in there and blow the jets out with compressed air. If that doesn't fix it I might just have to put it away for winter which sucks cause now is when I want to fish and duck hunt

[Deershooter]

Have you tried checking spark after it warmed up and shut down?

[delcecchi]

While you have it apart, you could run a fine wire (very carefully) through the jets just to make sure they are open.

[Dooley87]

Pulled carb apart, let it soak in carb cleaner for a awhile, dried it off, blew it out, the jets and ports seemed free and clear, reattached carb and went to prime the bulb with fuel and the hose was so stiff from being cold this happened

Starting to think that I'm not meant to get this motor going lol.

Bad part is fleet already pulled all their marine stuff so now I need to find a Johnson fuel line connection, hopefully in tune marine will have one.

[Surface Tension]

Get rid of the OMC connection at the tank and replace it with a male fitting with barbed end. Soaking and compressed air is good but it will take more then that to remove varnish and crud. As Del said use a wire. Remove the jets from from the carb first and then run a small wire though. The circuits inside the carb body, use spray carb cleaner with straw to flush them out and then a wire there as well. Look closely in the throat and you will see them, check for a good spray when you flush them out after the wire. Follow up again with the spray. This is to address the poor idle as you have a lean condition. The jerk you mentioned is a lean sneeze.

To clarify, your saying it'll run OK at higher RPMs. Will it stay running at those higher RPMs? If not you have a fuel level problem as well. Check the float drop. Also with float and inlet valve installed check its function. Tip the carb over and then then upright looking to see if the needle is moving freely. And or put a small section of hose on the inlet and blow through it. Do so the the carb upright and flipped over. You should notice the inlet valve shutting off when the carb it tipped upside down and opening when upright.

When you get the hose connection to the tank fixed. Test the OMC connection to the outboard by squeezing up the bulb and then depress the ball on the OMC connection. Fuel should flow freely out of it.

[Dooley87]

The omc connection at the motor is good, when I had the carb off I primed it to see if I would get a free flow of fuel to the carb and it did. I agree it's a good idea to just put a barb on the tank but not sure where to find those fittings locally.

When I noticed a rough idle a few weeks ago it would run wot fine when I slowed down at the dock it would jerk and die but was running wide open fine, when I tested it in a tank at home I couldn't get it to idle or run wot. I did check how the float was sitting and replaced the needle and seat even though the old one seemed to seat just fine.