Cylinder head bolts for 4hp Johnson twin?

[Birdseye]

Just bought one of these engines. Nothing wrong with it when purchased (vendor demoed it starting and running fine) but being me I decided to strip, inspect and clean it on arrival. And perhaps inevitably, I've sheared one of the bolts which was corroded in place.

I'm fairly relaxed about extracting it - there's plenty sticking out to grab hold of, and I have some plus-gas on the boat. But obviously I'll now need a replacement (will probably replace all six) and as a thoroughly metric mechanic (I even had to buy a set of imperial spanners specially!) I don't feel confident to measure / identify the bolts.

Anyone know what size I need? And is there anything special about cylinder head bolts, or will anything the right thread and length do? Suggestions of suppliers welcome too.

Cheers,

Pete

measure the od of the threaded bit and count the number of threads per inch. That will give you the bolt thread size. As for anything special - well unless they are pretty small diameter bolts, almost anything will do

 

[prv]

If anything else breaks on your new engine give me a shout and I will see if I have it in my engine in bits.

Cheers

Pete

 

[prv]

unless they are pretty small diameter bolts, almost anything will do

Like, for instance, the ones I posted about having ordered back on Saturday night?

Pete

 

[prv]

SUCCESS!

24 hours since I left it soaking in plus-gas (plus a top-up before leaving for work this morning) and it's just come free. I did also give it a brief blast with a fine blowtorch (on the bolt rather than the cylinders) but I'm not sure whether that had much to do with it. Looking down the hole all seems in order, but I will gently clean each of them with a tap before re-assembling with the new bolts.

Cheers for the moral support

Pete