Seafoam vs regular mix has?

[Wetwilly62]

Ran my boat today on 2 gallons of fuel with 2 cans seafoam cleaner. Ran awesome. 5100 rpm .Once I ran that out hooked motor back up to regular mix fuel. Dropped back to 3900 RPM's.? Anyone know why the difference?

 

[Scott Danforth]

because the tank with the regular mix has an issue?

 

[F_R]

Sea Foam loosened a chunk of carbon that lodged into a spark plug??

 

[Wetwilly62]

because the tank with the regular mix has an issue?

One would think so , but motor actually used less fuel on the the seafoam tank..

 

[Wetwilly62]

Sea Foam loosened a chunk of carbon that lodged into a spark plug??

Installed fresh plugs after tank of seafoam .

 

[GA_Boater]

because the tank with the regular mix has an issue?

Or the gas in the tank, vent issue or plumbing to the motor issue.

One would think so , but motor actually used less fuel on the the seafoam tank..

What does this mean?

 

[Wetwilly62]

Or the gas in the tank, vent issue or plumbing to the motor issue.



What does this mean?

I've been buying non ethanol 84 octane from the same place. I think it may be fuel.ran twice as long on half the fuel.

 

[F_R]

Installed fresh plugs after tank of seafoam .

OK, but did a hunk of carbon get in the new plug? Worth checking

 

[Wetwilly62]

OK, but did a hunk of carbon get in the new plug? Worth checking

Plugs were clean.. 1 understand these old 1977 55hp are a little higher compression. Maybe higher octane fuel may help , I may be battling some detonation or pre ignition. Issues. Or maybe just bad gas .Just cant get higher octane non ethanol where I am unless I go to race fuel.

 

[juno pierrat]

just to be clear, the 2 gallons and seafoam had oil too.

 

[Wetwilly62]

just to be clear, the 2 gallons and seafoam had oil too.

Yes , standard 50:1.

 

[schematic]

Dropped back to 3900 RPM's.? Anyone know why the difference?

More people in the boat?
Trim adjusted lower?
Bucking wind?

 

[Wetwilly62]

More people in the boat?
Trim adjusted lower?
Bucking wind?

Only me, non adjustable trim , ran same direction with both tanks.

 

[GA_Boater]

Why not try the small tank with only a 50:1 mix, no Seafoam? See what happens.

I do think you have a problem with the main tank or plumbing.

 

[Wetwilly62]

Why not try the small tank with only a 50:1 mix, no Seafoam? See what happens.

I do think you have a problem with the main tank or plumbing.

Gonna give that a try. Will update later with results. Thanks

 

[Scott Danforth]

Your not helping by running on 84 octane. Minimum should be 87

 

[roscoe]

Where in the world do you live that you can't get better gas.

Go here:

https://www.pure-gas.org

Pick your state or province, and find a station that sells better ethanol free gas.

 

[icwingman]

get some octane booster from an auto parts and try that, but i would drain all old gas out of tank, check all filters and do it again

 

[Wetwilly62]

Why not try the small tank with only a 50:1 mix, no Seafoam? See what happens.

I do think you have a problem with the main tank or plumbing.

https://youtu.be/lZtQPGizXVE

notice what I call flutter sound in this video. This is normal mix regular tank , the second video much smoother sound.with seafoam in small tank. With or without cowling

https://youtu.be/4fWyV9ao1UM

 

[schematic]

200 rpm is not a great difference. Certainly not a dead cylinder from ignition failure, as it would drop atleast 1000 rpm. Even fuel quality could cause this.