1996 Johnson V4 130HP Intermittent Power Loss

[rice_vi]

I have been trying to address this issue since I bought the boat about 5 months ago. The motor starts right up and runs perfectly for about 10-15 mins, then it losses power and slowly slowly revs down. The engine will rev fine in neutral, but bogs down in gear. I have replaced the Ignition coils, spark plugs and wires, removed the VRO and added a mechanical fuel pump, added a fuel/water separator, and removed and cleaned the carbs. I’m stumped and cannot afford to take it to a shop. Could it be the power pack, does that match up with my symptoms.

 

[saltchuckmatt]

I have been trying to address this issue since I bought the boat about 5 months ago. The motor starts right up and runs perfectly for about 10-15 mins, then it losses power and slowly slowly revs down. The engine will rev fine in neutral, but bogs down in gear. I have replaced the Ignition coils, spark plugs and wires, removed the VRO and added a mechanical fuel pump, added a fuel/water separator, and removed and cleaned the carbs. I’m stumped and cannot afford to take it to a shop. Could it be the power pack, does that match up with my symptoms.

Have you checked to see if the motor is overheating? Have you checked for spark after it has symptoms? Have you checked compression? Motor will always seem fine with no load....( Neutral )

 

[rice_vi]

I

Have you checked to see if the motor is overheating? Have you checked for spark after it has symptoms? Have you checked compression? Motor will always seem fine with no load....( Neutral )

I have checked and the compression is good on all cylinders. I don’t believe that the buzzer is connected, but it is peeing strong so I don’t assume it is overheating. Additionally, I have checked for spark but not immediately after symptoms.

 

[saltchuckmatt]

I

I have checked and the compression is good on all cylinders. I don’t believe that the buzzer is connected, but it is peeing strong so I don’t assume it is overheating. Additionally, I have checked for spark but not immediately after symptoms.

I

I have checked and the compression is good on all cylinders. I don’t believe that the buzzer is connected, but it is peeing strong so I don’t assume it is overheating. Additionally, I have checked for spark but not immediately after symptoms.

If it's peeing strong, than that just means the pump is working.... doesn't mean it's cooling. Could be bad thermostats or all the passage ways could be plugged. Having a alarm not hooked up would have only exasperate that problem. Overheat might set off a safe or limp mode.

Run the engine and shoot the top of the heads with a ir gun or hook up the alarm.

Highly likely that is where your problem is.

 

[racerone]

Test run with another tank and hose.-----And perhaps there is an issue with crankcase pressure to drive the fuel pump.

 

[rice_vi]

If it's peeing strong, than that just means the pump is working.... doesn't mean it's cooling. Could be bad thermostats or all the passage ways could be plugged. Having a alarm not hooked up would have only exasperate that problem. Overheat might set off a safe or limp mode.

Run the engine and shoot the top of the heads with a ir gun or hook up the alarm.

Highly likely that is where your problem is.

I just ran the motor on the water until the issue occurred and was able to leave my hand on the heads, it’s definitely not overheating.

 

[rice_vi]

Test run with another tank and hose.-----And perhaps there is an issue with crankcase pressure to drive the fuel pump.

How would I check this?