local source for Valve springs

I visited two ma & pa shops today and asked for 18# valve springs. I even brought in one of the stock ones from my tec ohv 5hp/power sport. The first guy basically told me to gtfo and sent me down the road. The place he sent me to was actually closer to my house. They had some springs that looked like they would work - they were heavier/stiffer and I could still compress them some with my fingers, but he couldn't tell me the spec on it. Should I assume it's about 18# and just use it anyway?

Will heavier springs have any adverse effects? Should I set the valve lash bigger? (what Should it be anyway? .004/.004, or .002/.003?)
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Active Member
I wouldn't assume anything, only use proven parts. No lawn mower shop is going to know what you're talking about if you're asking for 18# springs. Repair shops repair equipment using OEM parts, they typically don't modify it. Using stiffer valve springs won't improve anything unless you're running at higher RPM, then the spring rate should be increased accordingly. But only stiff enough to eliminate valve float at the engines highest RPM. Stiffer springs increase the engines rolling resistance which actually reduces horsepower and they also increase the load on the valve train which causes increased wear. So if your engine is close to stock and not running over 5000 RPM, I'd leave the stock springs in there. If you really want to go crazy with modifications, sell your Tecumseh and buy a clone. Then you have all the parts and support you could ever want.
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Thanks for the info on the rolling resistance - that's good advice. I plan on removing the gov, but probably not before I replace the carb, air intake, and exhaust. I understand there's plenty of support for clones, but this is what I have now so it looks like support is limited, eh?