OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Engines Questions On Briggs & Stratton Engines B&S 18.5 HP I/C twin cranking slow

I've got a B&S 18.5 HP I/C twin 42A707 Type 2238E1 that the starter motor won't crank past TDC anymore. With both the plugs out, it cranks freely, I have bypassed the solenoid etc and am using a 460cca battery with 60 amp jump leads straight onto the starter to try to get it to crank. Google searches reveal chit chat about a couple of things including valve adjustment, but this one isn't OHV, and wear in the top bush of the starter causing drag across the magnets, but this one is pretty good. Any other ideas?

This is a opposed L-Head engine. They do have a slight decompression bump ground on the camshaft. If these are worn down it can cause this but before tearing down verify that the starter is not worn out. These starters do tend wear out their bushings causing dragging against the magnets.

If it is the cam note that it is NLA and must be obtain either from a donor or as NOS.

Cheers thanks. How do I verify that the starter is or isn't dragging?

I guess you could fit one of these in each head. or you could fit a Victa powertorque decomp valve in each head but with the Enfield type you can close the valves once the motor is spinning freely
https://www.ebay.co.uk/itm/Brand-Ne...sembly-/401454401626?hash=item5d788c085a

The best way would to use a known good starter. Other than it takes experience in the feel of the starter as you hand turn it or disassembly looking for wear and rust.

Most of these oppose engines are approaching nearly 20 + yrs old now. I only seen one this in the shop and I couldn't even pull the flywheel because someone a big fat hammer to remove the flywheel previously and then over tighten the flywheel nut with an impact gun.

Check valve clearances first.....

Low valve clearances which L-heads tend to have after long term use seldom causes an engine to stop at the top a compression stroke; unless a cam lobe is heavily worn disabling the ACR function.