272 Sailfish

[Palmolotte]

I have a ‘96 272 sailfish with twin Yamaha s200 txru ( same yr). While running offshore yesterday, rpm’s would drop then come back up. 3900 down to +/- 3400 then back to 3900. Ran 75 miles and did this pretty much the entire trip. Any thoughts would be appreciated.

 

[freddy063]

were you riding up and down waves? both motors did the same thing? how loaded was your boat?

 

[Palmolotte]

were you riding up and down waves? both motors did the same thing? how loaded was your boat?

Seas were calm 1’-2’, glass at times. Both motors did the same but the starboard dropped more than port. The boat was full of gas (200g), rods, ice, 1 person on the run out and burned 150g including run back in.

 

[freddy063]

Seas were calm 1’-2’, glass at times. Both motors did the same but the starboard dropped more than port. The boat was full of gas (200g), rods, ice, 1 person on the run out and burned 150g including run back in.

when my boat had that trouble, it was only one motor and it was the a fuel issue , i pumped the primer ball and rpms stayed , so I changed the fuel filter, fuel pumps and fixed the fuel lines sharp turns. I would start there and see if you get the same response that I did.

 

[deepdesire]

Original fuel lines? Those are carbed motors correct? Sounds like fuel delivery issue, junk in carbs. Remove silencers look in carbs while running. you'll see the stream of fuel slow in the dirty carb when the motor slows. Do not miss that since I repowered.

 

[PointedRose]

Agree - first spots to check is the fuel lines, fuel filters, and or carbs.
Maybe run some Seafoam through

 

[Palmolotte]

I have a ‘96 272 sailfish with twin Yamaha s200 txru ( same yr). While running offshore yesterday, rpm’s would drop then come back up. 3900 down to +/- 3400 then back to 3900. Ran 75 miles and did this pretty much the entire trip. Any thoughts would be appreciated.

Original fuel lines? Those are carbed motors correct? Sounds like fuel delivery issue, junk in carbs. Remove silencers look in carbs while running. you'll see the stream of fuel slow in the dirty carb when the motor slows. Do not miss that since I repowered.

Thanks for both responses. I hope it’s just the filters. They are carbed, original lines and have the electric primer pump, not bulbs. The gas I filled up with did have ethanol so that may be contributing to the problem

 

[Palmolotte]

I’ll change filters n check the lines and carbs next time I’m at the boat.

 

[PointedRose]

I’ll change filters n check the lines and carbs next time I’m at the boat.

Check the hose clamps too. There could be a crack in the line somewhere allowing air or losing suction or something