| Author |
Message |
    
krossfire
New member
Username: krossfire
Post Number: 1
Registered: 06-2022
| | Posted on Saturday, March 04, 2023 - 08:04 pm: | 
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I bought this ST Lawrence today, supposed to be running condition, I noticed there�s no priming cup, is this unusual? Looks like it may have been plugged or welded, or possibly not drilled out on the casting, I think it�s a 3 hp any info would be helpful
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chris_spring
Senior Member
Username: chris_spring
Post Number: 251
Registered: 02-2019
| | Posted on Sunday, March 05, 2023 - 09:40 am: |
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My St. Lawrence dates to about 1925. The primer cup is on the cylinder head. The thing you seem to be showing in the pic below the label was simply part of the casting process.
Cheers!
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krossfire
New member
Username: krossfire
Post Number: 2
Registered: 06-2022
| | Posted on Tuesday, March 07, 2023 - 04:34 pm: |
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It�s actually on the head, where the primer cup should be, this isn�t a very good picture but I�m not home, I think it looks like it was welded over, then painted, I�ll likely have to drill it out the tap
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miro
Senior Member
Username: miro
Post Number: 1220
Registered: 11-2001
| | Posted on Thursday, March 09, 2023 - 03:29 pm: |
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Please be careful when you do the drilling. The passage for the priming cup, goes into the cylinder and the water jacket surrounds that passage.
You don't want to drill through the wall of that passage.
And it matters how the head is put onto the cylinder.
There's a right way and a wrong way.
The picture of Chris' engine is the right way.
I would think the slickest thing to do is to take the head off the engine, and make sure you know where the passage comes out in the inside of the cylinder.
I usuallly find that I can re-use the head gasket if it's not damaged when you take the head off.
Miro |
krossfire
New member
Username: krossfire
Post Number: 3
Registered: 06-2022
| | Posted on Sunday, July 16, 2023 - 07:41 pm: |
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I pulled the head off and looks like there was originally a priming cup but it's been plugged off or welded so I will have to drill out and tap for a new cup, I'm assuming it should be a 1/8 inch npt priming cup
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chris_spring
Senior Member
Username: chris_spring
Post Number: 265
Registered: 02-2019
| | Posted on Monday, July 17, 2023 - 10:30 am: |
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Please let us know how you make out.
Cheers! |
