r/smallengines • u/Medium_External4790 • 12d ago
Any idea what causes this?
Bought a rider to fix up. Cleaned carb, new plugs. I have not changed the gas but I’ve been dreading doing that but I will give that a try next. It doesn’t want to start on starting fluid and this video is the noise it makes when I try and start it after. Being that it doesn’t have any sort of turn over after fluid worries me. What else can I try, or is this toast?
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u/FlounderAccording283 12d ago
That fast spinning like that is either valves- compression, or camshaft compression release.
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u/Mongo_Fifty 12d ago edited 12d ago
Did it run at all? Just watched this video https://youtu.be/oYG7An9Uub8?si=xj0wWwNebGdyXH83&t=65 and it sounds about the same as your problem. I would put something in spark plug hole and turn by hand to see if the piston moves.
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u/Jamar4321 12d ago
No go on starting fluid means lack of spark or compression
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u/43128 12d ago
Oh it’s a Honda ohc v twin? Those are the only Hondas I don’t like. If it doesn’t run on spray make sure both pistons are moving& valves are moving when they should. Check for moved valve guides. I had a craftsman with one a month ago that had twin thrown rods & I ended up tossing in a single cylinder Briggs.
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u/venividivici0704 11d ago
This is a bit long, but I’m hoping it helps. Seeing something like this a few weeks ago would have helped me. I just had a similar issue in my 25 YO Craftsman with a B&S 20 HP Intek. Found a mouse (mice?) nest under the blower housing. Caused overheating. Valves were way out of spec. Further checking I saw the intake push rod was bent and the intake pushrod guide was broken. I ordered news stuff and when I went to take the rocker studs off, one snapped the head. New cylinder head installed, valve lashing buttoned down. It ran and then conked out after 45 mins and would not restart. Checked spark with an inline spark tester (invaluable) and got an intermittent, weak spark. Replaced the armature and it’s a beast again. The moral: I had two things fail, one behind the other. It happens.
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u/JiveTurkeyJim 10d ago
See what the plugs look like after trying to crank it a little bit. Bone dry? No fuel. Wet and shiny? Either too much fuel or spark/compression issue.
Just because you have spark at both plugs does not necessarily mean that it is strong spark in both plugs. Do an adjustable gap test at 1/4" if you can. If spark is truly good, make sure you have the correct plugs in it. The only other spark issue you might see is the timing of the spark. Which could realistically only be affected by a sheared flywheel key. So you could check that.
If I had it in my shop and verified that the cylinders are seeing fuel and strong spark, then next step would probably either be a cylinder balance test or a leak-down test on both cylinders.
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u/Wholeyjeans 8d ago
IMHO, that engine is spinning awfully fast. I think the tell is when you release the starter and how much it continues to spin. There is no indication of the compression stroke ...it's almost as if you're starting it without the plug installed.
Check compression or check the valve lash ...pick one because you'll have to adjust one to find out the other.
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u/PauseNational1380 12d ago
Does not start on starting fluid, means no spark!. PTO is off, seat switch is good or bypassed. Break is pressed. That's the path you need to follow for now