What Are the Signs & Symptoms of a Bad Primer Solenoid?

A primer solenoid is something you may have heard clicking after pushing the key in and out. It is an electromagnet with a steel rod at the center.

It is an electric valve that creates pressure in the fuel lines so that fuel flows to the carburetor.

In the old engines, the solenoids were responsible for restricting air going into the carburetors. This is why solenoids are associated with ‘choking’.

A bad primer solenoid causes problems in the smooth running of the engine. This article will discuss the symptoms of a bad primer solenoid in detail.

What Sign You Should Look for to Detect a Bad Primer Solenoid?

Signs of a bad primer solenoid are:

  • The motor is hard to start when cold.
  • Despite difficulties in a cold start, the motor is easy to start when warm.
  • The primer bulb gets hard.
  • The motor starts to spin.
  • The motor sometimes starts firing, i.e, misfires occur.
  • The engine chokes out and the motor starts to spin and fire again.
  • More smoking out of the motor than usual.
  • The engine primes repetitively.
  • The red lever in a normal situation should be at the top of the solenoid. If it is pushed back while the engine is running, the engine will get flooded. This may be an indicator of a bad solenoid.

What Are the Symptoms of a Bad Primer Solenoid?

A bad primer solenoid can show some symptoms. These are:

No ‘Click’ After Pushing the Switch

In reality, it is very normal to not hear the click. Especially just after pushing once. Sometimes, you have to try twice to hear it. It usually then clicks!

This happens because sometimes, the lever just gets stuck.

However, it is an indicator that the solenoid may have gone bad.

Difficulty Starting the Engine

The engine seems difficult to start. As I was saying, having to push the key twice or more is a sign of a bad solenoid. This means your engine is not starting as easily.

The gasoline needs to be thrust to the intake manifold. This needs pressure. This pressure is created when the fuel primer bulb is being squeezed. The pressure can also be created by the fuel pump flowing.

The primer solenoid is the electrical device that allows this to happen.

This is why when the primer solenoid is bad, the engine faces difficulty starting. The engine either doesn’t start when cold or takes time to start.

Difficulty in Keeping the Engine Running

You may have to give the pump a real squeeze to pump fuel. Meanwhile, you will have to look for fuel leaks as well.

Because of a bad solenoid, fuel does not get pushed or pressurized into the intake chamber.

Back Pressure on Water

As it is hard to start the motor during cold, it is hard to start in winter. Additionally, during winter, you may realize that the back pressure on exhaust on the water is high.

The pressure is not high on the muffs.

Primes and Fires on Land

When the primer solenoid has gone bad, the motor is difficult to start on the water.

Moreover, you may notice the engine priming and misfiring when on land.

Test with Volt-Ohm Meter

A small test to check primer solenoid health can be conducted with a volt-ohm meter.

Notice two wires coming out of the solenoid. At first, remove the wires from their respective connectors.

Set your VOM at a resistance scale that is low. Now place the leads of the Volt-Ohm meter to the two wires.

If you have a good prime solenoid, you should get about 4 Ohms of resistance.

Make sure to clean the wires before putting them back on.

How Should You React If You Detect a Bad Primer Solenoid?

If your bulb is primed, then it comes down to working the primer.

Start your motor by turning the red handle while you pump the primer bulb.

This bypasses the electronic part of the primer. As a result, gas will be pushed directly behind the carburetors.

Once your engine has started, shift the red handle to its initial position (normal position).

A bit tedious process, but your engine will work. This is a temporary solution. You should probably get your solenoid fixed or replaced by a professional.

You can also buy parts online and then fix the solenoid yourself. The parts can also be bought through manufacturers directly. In that case, be aware of the prices of each part to avoid getting scammed.

But do double-check the engine after fixing it! Just because the primer solenoid now clicks, does not mean the issue is fixed.

To double-check, remove the primer and pump up the bulb. Then turn the key, press in after that. Check if the fuel is trickling from the line fitting.

The filter inside the primer can get clogged often. You need to address this issue otherwise the engine wouldn’t budge.

Is Replacing a Bad Primer Solenoid Typically Expensive?

The entire primer solenoid unit costs around $170. But the spare parts cost much lower, around a few bucks. The parts can cost anywhere between $15, up to a maximum of $100.

Replacing a single transmission shift solenoid costs around $15-100.

Replacing a pack costs around $50-300. The cost of course depends on the model of your engine and infrastructure.

Getting service from a professional usually costs more. The service charge comes around $120-400.

The total cost then becomes approximately around $250-600. This is quite expensive undoubtedly. However, you can troubleshoot minor solenoid problems yourself.

How Often Should You Inspect or Service the Primer Solenoid?

A typical solenoid lasts for about 1-2 years. The valve is supposed to last for a year or so. Regular maintenance can prolong the lifespan of it though.

Even if the solenoid goes bad, you can drive it. The troubleshooting method is given in this article too. However, once the engine shuts entirely, you have to take action.

You can replace the solenoid once it is bad. Regular maintenance includes replacing damaged components, cleaning the valves, getting rid of dirt and debris. You must inspect the solenoid cap for cracks every time you face difficulty with the engine.

Inspect the solenoid when the mentioned symptoms occur. Also, inspect it during regular maintenance done weekly or monthly.

Service the solenoid parts when the engine is getting affected too much. It is not ideal to run the engine with a bad prime solenoid.

Final Thoughts

I have so far given you the signs, symptoms, and troubleshooting methods for a bad prime solenoid.

But when you face similar problems with your engine, do not automatically assume the solenoid is bad. There are many reasons why an engine fails to start. A bad outboard ignition coil, fuel air leak, etc. can also lead to engine spluttering and misfires.

Remember to check each part of the engine carefully, read more about the reasons why the engine slows down or stops. Keep an eye for the additional symptoms.

This way you will detect the exact problem with your engine.

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