Hi Harry, It could be compression too low when hot but you really need a compression tester to check that .
Ignition Coil: If the ignition coil is getting weak when hot, it might cause intermittent starting issues. You can test for spark when the engine is hot.
Compression and Engine Condition
Compression Check: Use a compression gauge to ensure the engine has adequate compression. .
Air Leaks: Check for air leaks, particularly around the intake manifold or carburetor gasket. An air leak can lean out the mixture and make it harder to start.
Possible Considerations
Overheating Issues: If the mower is overheating, it can lead to "heat soak" issues, where it gets hard to start after being turned off briefly. Check for blockages in the cooling fins and ensure the engine is not excessively dirty.
Cleaning and Maintenance: Regularly clean the air filter and ensure it's not blocked, as a dirty air filter can affect performance.
I'd check fuel flow when it won't start as sometimes the fuel cap breather doesn't work ,also when you turn the mower off turn the fuel tap off that will rule out over fueling.
Hi Norm,
I'm sure you would have Deutscher kickback problems if you used a Powertorque or the Honda motor.
When you look at my video of starting the Powertorque without a blade plate the engine spins fast from the starter cord but I remember starting Victa 24's with the side pull starters and they were so much slower to spin over as you just end up getting drag from the v belt drive turning the blade plate,this just adds to a kickback problem.
You can't compare one motor that doesn't kickback to another that does unless you know all the specs and condition of the motors as there are a few things that contribute to kickback.List below of specs that can be changed so the engine can suit other applications.
Compression Ratio: Higher compression ratios can lead to stronger kickback. A higher compression means that the engine requires more force to turn over, which can cause the starter mechanism to experience sudden reversal when the ignition occurs.
Ignition Timing: Incorrect ignition timing can significantly contribute to kickback. If the spark plug fires too early while the piston is still rising (before top dead center), it can lead to a violent reaction that causes the engine to kick back.
Flywheel Weight: A heavier flywheel tends to smooth out the rotation of the engine, helping to prevent sudden changes in momentum that can lead to kickback. Conversely, a lighter flywheel may exacerbate kickback.
Crankshaft Design & Weight: The design and weight of the crankshaft can influence the inertia during startup. A heavier crankshaft may absorb some of the shock associated with kickback, whereas a lighter one may not.
Starter Type: The type of starter (manual pull starter, electric starter) can also affect the experience of kickback. Manual starters can provide less mechanical advantage than electric starters, potentially leading to more noticeable kickback.
Fuel Mixture: The air-fuel mixture can affect engine performance. A rich mixture may lead to lower temperatures and incorrect combustion timing, which can contribute to kickback.
Engine Condition: Worn components, such as valves, piston rings, and bearings, can lead to inefficient combustion and increased likelihood of kickback.
Cold Engine Effects: Starting a cold engine can change its dynamics. Increased friction and oil viscosity can contribute to the behavior of the engine when it first starts, potentially increasing the chance of kickback.
Factors Affecting Kickback Due to Cam Design
Camshaft Profile: The shape and design of the cam lobes influence the timing and duration of valve opening and closing. A more aggressive cam profile can result in quicker valve motion, potentially increasing the likelihood of kickback if the engine is not designed to manage such forces effectively.
Timing of Valve Events: If the camshaft timing (when the intake and exhaust valves open and close relative to the position of the piston) is not optimized, it could lead to back pressure during the compression stroke. This can create resistance when attempting to start the engine, leading to kickback.
Compression Ratio: The cam design can influence the effective compression ratio of the engine. Higher compression ratios can lead to increased resistance when starting, resulting in more potential for kickback. Camshafts designed for performance often increase compression at specific points in the engineβs cycle.
The design of the decompressor in a small engine can play a significant role in reducing or eliminating kickback during starting.
Yes the Honda 4 stroke crank doesn't look to have much weight out from the main shaft ,the early Victa full crank has a lot more outer weight on the crank ,If adding weight to a powertorque is time consuming why not just fit the full crank 2 stroke motors to the Victa 24 mowers.
There are a lot of different specifications a factory can change on a motor to stop it kicking back when starting when used in other applications .
I see a lot of people that have an original working mower from the factory then when the engine is worn out they just take an engine that is not to the factory specification to suit their mower and fit the wrong motor then it kicks back when starting.
Then you end up with people selling cheap mowers that don't run.
