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Hi,
First, thank you for taking the time to read this post. I currently own a 1985 Boston Whaler 15ft with a Johnson Seahorse 70 long shaft. The motor idles great and runs great at WOT. However, between 1800-2200RPM when trying to get onto a plane it seems to have a delay in throttling up. Here is a video that might help (https://youtu.be/FYatYUTQ12g). In the video I hold the throttle steady at 2000RPM it almost sounds like it has a miss after 3 seconds I open the throttle to max. Once the motor gets past the delay it runs great, the best I can describe it would be a dead spot in the throttle. I did turn off the motor when it was doing this and checked the spark advance and it was fully advanced. I have tried hitting the primer when this happens and the engine then wants to stall. I have also pumped the primer bulb and it does not seem to help. Below is some things I have done to the motor:
*Cleaned all three carbs (ultrasonically) and blew out with compressed air. Rebuilt carbs but did NOT dip them in solvent overnight.
*Replaced spark plugs using Champions (can't remember the exact make but they are the right ones)
*Rebuilt fuel pump
*Replaced all gas lines going to the carbs and primer/choke solenoid
*Replaced rectifier (tach was not working)
*Replaced gaskets on the airbox (both front and back)
*When the carbs were off I checked the Reed valves none were bent or broken. Some carbs spit (top one esp.) a little gas out at idle but none at WOT all seem to have an equal amount of gas coming out of the center jet at WOT.
*At WOT all throttle plates are horizontal and even with each other
*Replaced head gasket (water was getting into the bottom cylinder) and thermostat
*Compression from top to bottom is: 140, 135, 140 PSI
*Performed a link and Sync on the water. It got some of the delay out but not all.
*Ohm tested all of the coils I can't remember the exact reading but it was in spec (I think it was 600) and they were all very close to each other resistance wise (2-3 ohms)
*Checked stator with ohm meter it was also within spec and the battery is charging
*Replaced prop (13x19) with a new BRP Aluminum one with 13.25x15
I did not check the trigger. I did unplug it and checked the connections all seemed fine no corrosion. The Power Pack seems to be the original one but not sure and I do not know how to test it. It has the brown silicon backing on it.
Any help would be MUCH appreciated.
--Ben
First, thank you for taking the time to read this post. I currently own a 1985 Boston Whaler 15ft with a Johnson Seahorse 70 long shaft. The motor idles great and runs great at WOT. However, between 1800-2200RPM when trying to get onto a plane it seems to have a delay in throttling up. Here is a video that might help (https://youtu.be/FYatYUTQ12g). In the video I hold the throttle steady at 2000RPM it almost sounds like it has a miss after 3 seconds I open the throttle to max. Once the motor gets past the delay it runs great, the best I can describe it would be a dead spot in the throttle. I did turn off the motor when it was doing this and checked the spark advance and it was fully advanced. I have tried hitting the primer when this happens and the engine then wants to stall. I have also pumped the primer bulb and it does not seem to help. Below is some things I have done to the motor:
*Cleaned all three carbs (ultrasonically) and blew out with compressed air. Rebuilt carbs but did NOT dip them in solvent overnight.
*Replaced spark plugs using Champions (can't remember the exact make but they are the right ones)
*Rebuilt fuel pump
*Replaced all gas lines going to the carbs and primer/choke solenoid
*Replaced rectifier (tach was not working)
*Replaced gaskets on the airbox (both front and back)
*When the carbs were off I checked the Reed valves none were bent or broken. Some carbs spit (top one esp.) a little gas out at idle but none at WOT all seem to have an equal amount of gas coming out of the center jet at WOT.
*At WOT all throttle plates are horizontal and even with each other
*Replaced head gasket (water was getting into the bottom cylinder) and thermostat
*Compression from top to bottom is: 140, 135, 140 PSI
*Performed a link and Sync on the water. It got some of the delay out but not all.
*Ohm tested all of the coils I can't remember the exact reading but it was in spec (I think it was 600) and they were all very close to each other resistance wise (2-3 ohms)
*Checked stator with ohm meter it was also within spec and the battery is charging
*Replaced prop (13x19) with a new BRP Aluminum one with 13.25x15
I did not check the trigger. I did unplug it and checked the connections all seemed fine no corrosion. The Power Pack seems to be the original one but not sure and I do not know how to test it. It has the brown silicon backing on it.
Any help would be MUCH appreciated.
--Ben
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