beeracuda410
New member
Hello All,
I have a single 2021 Mercury 300 4 stroke 4.6L V8 mounted on the back of my Sailfish 241cc.
It's identical to the 300 Verado except it does not have the AMS, just traditional trim system and 3rd party electric hydraulic steering.
The boat only has 45 hours. There is a 110 gallon fuel tank.
Over 4000 RPM's, the engine has started to hesitate, it makes the entire outboard hop up and down like you're hitting bottom. Below 4k, seems to run fine.
I did fill it up with regular 87 octane with 10% ethanol before launching in May while it was on a trailer at a local gas station.
The hesitation started when the fuel level got down to 50%(+/-)
I have since added 1 gallon of Sea Foam, and 2 bottles of Lucas octane booster, since I am not sure if this engine has a minimum octane rating or not.
The fuel additives did not help after running another 10% of fuel and additives through it.
Sailfish does not install remote fuel water separators. The only one is mounted under the cowling, I removed it, blew it out into a clear bottle, there was just a tiny bit of water, could have been residual in the bottle, but not enough to to cause this IMHO.
Took boat out again after cleaning out filter, same result, hesitation over 4k.
Next I'm looking at toping fuel tank off with 89 or 93
Or Replacing spark plugs. Nickel or Iridium is best? Is ILFR6GE the correct part #?
I also read it could be a spark plug wires or coil. I checked all connections, seem fine to me.
Am I hurting anything running it below 4K?
Just want to rule everything out that I can before I'm forced to take it to MarineMax and let it sit for weeks and get clobbered over the head.
Any wisdom would be greatly appreciated.
Thank you!
I have a single 2021 Mercury 300 4 stroke 4.6L V8 mounted on the back of my Sailfish 241cc.
It's identical to the 300 Verado except it does not have the AMS, just traditional trim system and 3rd party electric hydraulic steering.
The boat only has 45 hours. There is a 110 gallon fuel tank.
Over 4000 RPM's, the engine has started to hesitate, it makes the entire outboard hop up and down like you're hitting bottom. Below 4k, seems to run fine.
I did fill it up with regular 87 octane with 10% ethanol before launching in May while it was on a trailer at a local gas station.
The hesitation started when the fuel level got down to 50%(+/-)
I have since added 1 gallon of Sea Foam, and 2 bottles of Lucas octane booster, since I am not sure if this engine has a minimum octane rating or not.
The fuel additives did not help after running another 10% of fuel and additives through it.
Sailfish does not install remote fuel water separators. The only one is mounted under the cowling, I removed it, blew it out into a clear bottle, there was just a tiny bit of water, could have been residual in the bottle, but not enough to to cause this IMHO.
Took boat out again after cleaning out filter, same result, hesitation over 4k.
Next I'm looking at toping fuel tank off with 89 or 93
Or Replacing spark plugs. Nickel or Iridium is best? Is ILFR6GE the correct part #?
I also read it could be a spark plug wires or coil. I checked all connections, seem fine to me.
Am I hurting anything running it below 4K?
Just want to rule everything out that I can before I'm forced to take it to MarineMax and let it sit for weeks and get clobbered over the head.
Any wisdom would be greatly appreciated.
Thank you!