Topic: 1955 Fleetwin, running hot? – Page 3 – Antique Outboard Motor Club,Inc

This topic has 49 replies, 9 voices, and was last updated 9 years, 2 months ago by ray-schaber.

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June 16, 2016 at 4:09 am #38387
beerman57
Participant
I agree, good catch. I don’t think I’ve ever seen a cyl. head with a plug at the bottom like that, have I? UM, all that water is being dumped in the lower cowl?
June 16, 2016 at 10:10 am #38389
shoestringmariner
Participant
Terrific, mystery solved. Thanks so much guys. I don’t suppose I can ask if anybody has a photo or image of what it Welch plug is?
June 16, 2016 at 11:05 am #38391
frankr
Participant
US MEMBER PAY BY CHECK
Welch plug is also missing in the exhaust housing picture. A Welch plug is a simple aluminum disc that is cup shaped. When you place it in the cavity and flatten it out with a hammer & suitable punch, it expands in the hole. That locks it tightly in the hole. Also sometimes called a "core plug" or a "freeze plug".
June 16, 2016 at 11:32 am #38393
shoestringmariner
Participant
Freeze plug I understand…I see the hole you are referring to, but if that’s the case, wouldn’t there be tons of water pouring out of the cowl? The only water that I can see exiting this motor is coming from the stem
June 16, 2016 at 12:03 pm #38395
fisherman6
Participant
US Member
Very good catch, Don. That is most likely your only problem. Replace that plug and you should be good to go. I have a ’58 Johnson 7.5 that blew out the one on the side just above the one you have missing. Without the passages in the cylinder head plugged the leg doesn’t get water flow where it needs it. I replaced the Welch plug and all is well with coolingreat now. I would be willing to bet you will have the same result.

If you don’t see water running out of the lower cowl, I do find that strange, however. I had water pouring out all over with the side Welch plug missing.
-Ben

OldJohnnyRude on YouTube
June 16, 2016 at 1:20 pm #38402
fleetwin
Participant
US Member
Well, the 55 Fleetwin did not have a lower cowl, so the water would have been dumping right out of the cylinder head under the engine cover. Was water dumping out of the bottom of the head or not? Don’t really understand what you meant by "coming from the stem". Perhaps you can point it out in one of your pictures. I tried to find the part numbers of these core plugs but the 1955 stuff seems no longer online at marineengine.com.
Do you see the bottom of the cylinder head where the core plug should be in your top picture?
Please be sure to order a new OEM impeller along with lower seal parts along with the two core plugs, the gearcase is easily removed now that the powerhead is off.
June 16, 2016 at 1:43 pm #38404
dan-in-tn
Participant
US Member
ME shows 1957 as #202310 X 2 for cylinder head top & bottom. Not sure they are the same, but should be if that helps. May be the same as some carburetor kit welch plugs. Hope that helps!

Dan in TN
June 16, 2016 at 1:51 pm #38405
fisherman6
Participant
US Member
Dan is right. The plugs are the same and they are the same as in some carb kits. In fact, I believe the OMC carb kit for that motor should contain the plug you need. The plug I replaced in my ’58 was a leftover from a carb kit. I think that carb kit was for a 1987 Evinrude 2.5 but it’s the same plug. Also, the 7.5 head has 3 Welch plugs. I’m pretty sure that’s the only size engine with 3 of them in the head.
-Ben

OldJohnnyRude on YouTube
June 16, 2016 at 4:22 pm #38413
beerman57
Participant
Shoestring, what diameter? I’ve kept some carb kit welch plugs.
June 16, 2016 at 4:52 pm #38414
shoestringmariner
Participant
quote fleetwin:

Well, the 55 Fleetwin did not have a lower cowl, so the water would have been dumping right out of the cylinder head under the engine cover. Was water dumping out of the bottom of the head or not? Don’t really understand what you meant by “coming from the stem”. Perhaps you can point it out in one of your pictures. I tried to find the part numbers of these core plugs but the 1955 stuff seems no longer online at marineengine.com.
Do you see the bottom of the cylinder head where the core plug should be in your top picture?
Please be sure to order a new OEM impeller along with lower seal parts along with the two core plugs, the gearcase is easily removed now that the powerhead is off.

Apologies, I don’t know the proper terminology like you guys here…I meant the engine cover. There is or should I say WAS no water spilling out there, or at least I never noticed at the time of overheating. There is a possibility that it was coming out of the cover on the right side of the motor. I did a few barrel tests initially before hitting the lake, and there was no leakage then. But maybe when I hit WOT, it blew out from the higher pressure and I just didn’t notice. I am going to reassemble and run it Friday night (after checking the welch plug)

I meant by the stem, that water was coming out at the bottom of the exhaust tube. (the port at the middle of lower section). Not sure what that part of the motor is called…I guessed by calling it a stem 🙁
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