Starting fluid spraying back out of air filter

F

first_wang

Forum Newbie
I have a Toro 21472 that won't start. I tested it by spraying starting fluid into the air filter. When I pull the starter cord, the starting fluid sprays back out of the air filter instead of being drawn in.


What could be causing this, and how would I go about fixing it?


Additional info: spark plug shows spark, and there's some compression resistance when I block the spark plug hole with my finger.
 
Can think of three things that might cause that:

1. cam timing is off. If the engine was rebuilt then someone did not time it right. If this happened during use then it is a plastic cam machine that the cam lobes moved on the steel part of the shaft. Not totally unheard of.

2. The exhaust is plugged up. Critter nest or insects like mud daubers. It does happen.

3. The intake valve is way too tight, or stuck open. Can happen too.
 
first_wang said:
I have a Toro 21472 that won't start. I tested it by spraying starting fluid into the air filter. When I pull the starter cord, the starting fluid sprays back out of the air filter instead of being drawn in.


What could be causing this, and how would I go about fixing it?


Additional info: spark plug shows spark, and there's some compression resistance when I block the spark plug hole with my finger.
Click to expand...
Pull valve cover and inspect valves.
 
Thanks, that's really helpful! For context, I already had the valve cover off and noticed both rocker arms have some play, with the top one noticeably looser than the bottom one - not sure if that points to one of these three causes. Here's a video of me pulling the starter cord with the cover off, in case it helps:
https://drive.google.com/file/d/1QxLgTcejH3osiSRfQPDpDGVBiy6rA35i/view?usp=sharing.
Could you walk me through how I'd check each of these? Specifically: how do I check if the cam timing is off without a full teardown, how would I check the exhaust for a blockage, and how do I check if the intake valve lash is too tight or if it's stuck open? Want to make sure I'm checking in the right order before I go further.
 
Start with the simplest/cheapest possible solution first - Is your exhaust blocked?

Turn the engine over by hand (or get someone else to do it). Put a finger /hand over exhaust - you should be able to feel the air pressure rise (as exhaust valve opens) & fall as exhausts valve closes. If you can't feel it, its blocked or exhaust valve not opening.

If blocked, you may be able to take a piece of wire (or similar) into exhaust opening, wriggle it around in every direction - repeat above.
If exhaust valve not opening - much bigger problem. If you do not have the skill to diagnose/repair - take mower to repair shop .

FYI: - Staring fluid should never need to be used and can cause expensive damage to your engine. :devilish:
 
Thank you all for your help! I adjusted the valve lash but the engine still wouldn't start. Based on a video I saw online, I put about 5ml of gasoline into the spark plug hole and tried to start it. After a few pulls of the starter cord, it became stuck and I couldn't pull it anymore. I removed the spark plug to relieve any hydro-lock, but the cord is still stuck and won't pull even with the plug out. What should I do next, and how should I go about fixing this? Thanks.

20260731_115200.mp4

drive.google.com drive.google.com
 
depends how good you are with mechanical things as to what to do next. The two problems may not even be related, or maybe you got the valves too tight and one is hitting a piston etc..
 
Hello F.,

Can you provide the information that is etched/engraved into the flat side of the engine block? It will be on the side opposite of the carburetor and fuel tank.

The number you provided is for a Toro Recycler mower chassis; the engine is made by Briggs and Stratton.
 
1785706583299.pngengine is a Briggs & Stratton model 104M0200. After clearing the hydro-lock, I tried again with just a small amount of gasoline in the spark plug hole. The engine still won't start, even though the spark plug is sparking fine. What should I check or try next?
 
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