I have a 1996 Craftsman 4-stroke 9 hp 26” Snowblower (Model 536.886260). The engine is a Tecumseh HMSK90-156536D. It threw a connecting rod. I took the sump cover off and replaced the connecting rod (the crank final was undamaged). The timing marks were about ten teeth off so I realigned the crank and cam timing marks. I put the sump cover back on, remounted the engine and filled the oil.
When I run the electric starter it will not start. It’s getting spark and fuel. I removed and grounded the plug and am getting a good spark. If I put a torch to the muffler while it is cracking I get explosions, so I know it is getting fuel. I’ve tried starting fluid with no results.
Not being well trained on small engines, I thought maybe it’s firing on the exhaust stroke. So I got back into the engine thinking I would rotate the camshaft 180 degrees and re-assemble. Well once into the engine I realized that because of the “little spring thing” on the back of the camshaft to lift the intake valve a little higher during low speed, it is not possible to reinsert the camshaft 180 degrees off.
Can anyone suggest what I might try next?
#2
BWH
An easy way to check if the valve timing is close to correct is to check compression with a gauge.
You might also try just pulling the plug then slowly crank the engine over making sure that you have compression somewhere near the top of the piston stroke.
It is troubling that you found the timing marks ten cogs off, I have never had the timing jump after throwing a rod but I have only done a few myself. It really makes me wonder if somehow it is still off.
Maybe someone with more small engine experience sees this they can shed some light.
the statement about it being about 10 teeth off, makes me wonder if you are not mistaking another mark for a timing mark. If you pull the side cover back off to double check, post a good picture of the camshaft and crankshaft with everything installed so we can see what it looks like.
BWH, Thanks for your thoughts. I’m getting 110 lbs of pressure. There was no scoring on the cylinder wall when I pulled the piston.
IlEngine, I’ve attached a photo of the timing marks.
WHAT I DIDN’T TELL YOU, AND BELIEVE IRRELEVANT:
Additionally, I’ve posted two photos of the damage that was done when the engine threw the rod. A short block is no longer available so I, wire brushed the surface and coated the exterior of the short block with marine JB Weld (petroleum proof) and then ground it down so the electric starter would mate with the flywheel (the damage was on the short block under where the starter mounts). On the interior of the short block, I wire brushed the surface and coated a piece of soda can 100% with JB Weld marine and applied it to the interior. JD Weld Marine was allowed to cure for 3 days before reassembly.
Il Engine, You may be right. During all the rebuild, I have not removed the shroud. I will tomorrow. I'll pull the flywheel and see if the keyway is damaged. Thanks for your input, I'm lost for a solution.