Application – marine engine in a 1994 Tige Ski Boat
Engine 2010 5.7L Vortec Mercruiser
Edelbrock 1409 marine carburetor - 4 barrel with electric choke, 600 cfm, 30cc accelerator pump, "J" tubes, etc
Electric fuel pump kit - low pressure 4-7 psi electric fuel pump
Delco Voyager ignition kit - Voyager distributor with Electronic Spark Timing (EST), High energy ignition coil, 8mm marine spark plug wires and spark plugs
I replaced the original engine about 2 years ago, At that time, I spent a far amount of time to get acceptable performance by using different metering rods, jets and step up springs. Probably should have written down what I ended up with but I didn’t. Think I ended up being slightly on the rich, power side. Ran well for waterskiing where quick response is required at around 3500 RPM to maintain speed as skier pulls against boat and then relaxes pull as they turn. I’m using an automated speed control so that there is only about 20 RPM difference from the high and low RPM during normal operation.
So much for the background.
Now the engine is performing poorly. Doesn’t idle very well. Can smell gas, so must be running too rich. Pulling skier out of the water, the engine seems to stumble. Then while skiing, the engine surges. Probably the automated control wants to increase RPM but the engine doesn’t respond. So the automated control opens the throttle further and then the engine finally responds with more power then is needed.
Initially, the problem would go away after about 10 minutes of skiing. Now it happens even after 45 minutes of skiing but not constantly.
I’ve pulled the plugs – they all look good. Pulled the distributor cap – okay there also.
Did find a problem where the choke linkage became disconnected but this has been fixed. The choke does fully open when the engine warms open and this take only a minute or so.
Sprayed staring fluid on the carburetor gaskets to see if there was a vacuum leak but didn’t find anything.
I’ve ordered a carb rebuilt kit which will be here the end of the week. I’m going to open the carb up, so I’d need to at least replace the gasket below the airhorn anyway. This time I’ll write down what jets, rods and springs I’ve got. Be a couple of days before I can get to the boat.
What should I be looking for? Any troubleshooting tips?
Thanks, Bruce
Engine 2010 5.7L Vortec Mercruiser
Edelbrock 1409 marine carburetor - 4 barrel with electric choke, 600 cfm, 30cc accelerator pump, "J" tubes, etc
Electric fuel pump kit - low pressure 4-7 psi electric fuel pump
Delco Voyager ignition kit - Voyager distributor with Electronic Spark Timing (EST), High energy ignition coil, 8mm marine spark plug wires and spark plugs
I replaced the original engine about 2 years ago, At that time, I spent a far amount of time to get acceptable performance by using different metering rods, jets and step up springs. Probably should have written down what I ended up with but I didn’t. Think I ended up being slightly on the rich, power side. Ran well for waterskiing where quick response is required at around 3500 RPM to maintain speed as skier pulls against boat and then relaxes pull as they turn. I’m using an automated speed control so that there is only about 20 RPM difference from the high and low RPM during normal operation.
So much for the background.
Now the engine is performing poorly. Doesn’t idle very well. Can smell gas, so must be running too rich. Pulling skier out of the water, the engine seems to stumble. Then while skiing, the engine surges. Probably the automated control wants to increase RPM but the engine doesn’t respond. So the automated control opens the throttle further and then the engine finally responds with more power then is needed.
Initially, the problem would go away after about 10 minutes of skiing. Now it happens even after 45 minutes of skiing but not constantly.
I’ve pulled the plugs – they all look good. Pulled the distributor cap – okay there also.
Did find a problem where the choke linkage became disconnected but this has been fixed. The choke does fully open when the engine warms open and this take only a minute or so.
Sprayed staring fluid on the carburetor gaskets to see if there was a vacuum leak but didn’t find anything.
I’ve ordered a carb rebuilt kit which will be here the end of the week. I’m going to open the carb up, so I’d need to at least replace the gasket below the airhorn anyway. This time I’ll write down what jets, rods and springs I’ve got. Be a couple of days before I can get to the boat.
What should I be looking for? Any troubleshooting tips?
Thanks, Bruce