Boat engine starts but dies when put into gear - Troubleshoot your engine
With these 9 motor-specific tests, you’ll be able to learn why your engine starts but dies when put in gear. Regardless if your inboard boat won't go into gear, or you have an outboard engine, we have also gathered solutions and tutorials depending on the cause you uncover with these tests.
Our goal is also to help boat owners save money with our resources, so we begin with the cheapest tests. We hope this helps whether you are on a sailing boat, a speed boat, a pontoon boat, a fishing boat or if you managed to install an engine on your kayak. Don’t hesitate to reach out with some feedback.
Top questions about engine stalling when shifted into gear
Why does my boat motor die when I go into gear?
The problem can come from different parts of your engine. It could be one of the cylinders not firing, or the fact that your compression is not within the proper range. Your issue could also come from a bad spark plug or disconnected plug wires. Finally, you could also have a fuel supply issue causing your engine to misfire.
So we have created this series of troubleshooting tests so that boat owners can find out what exactly causes their engine to stop when switched into gear.
What should I do if my plug is not generating a spark?
The first thing to do is a quick test to find out if the missing spark comes from a faulty plug or a faulty plug wiring. To do that, switch the bad plug with one that works and do another spark test. Is the spark still missing at the same place or is it now missing to the allegedly faulty plug’s new position? If it stayed, the plug wiring was bad, if it moved, the plug was bad.
If it's a plug issue, you need to inspect the plug’s color, and replace or clean the plug according to the result. A bad plug can be an indicator of an improper fuel mixture so you might also need to readjust the float. (see test 4)
If it's the wiring, change or clean it (see test 5).
What is the normal cylinder compression for inboard and outboard motors?
- Two strokes recommended compression: 90-130 PSI.
- Four strokes recommended compression: 160-220 PSI.
How do I know if I need to clean or replace spark plug wires?
You first need to inspect the wiring, to do that, lay your wires flat on a clean surface, inspect them for cracks, signs of bare metal, or burnt marks. If you find that, you’ll need to change the wiring.
Then, check for corrosion markings on the metal connectors (the wire’s ends). If you find your connectors to be shiny, you are fine, but otherwise, clean them off by putting WD 40 on a clean cloth.
If you find that the metal connectors are bent out of shape, the issue could be that so take one of your working connectors and switch them up to test if that's your issue. You might need to replace them.
My spark plug is whitewashed, what does it mean?
A whitewashed plug means your plug is running too hot. Either because the plug’s heat range is not correct, or because you have an air/fuel mixture that’s too lean.
You should install a new plug with the right heat range. After that, you should adjust the float to fix the mixture ratio issue. See test 4 for more information.