Loss of RPM’s

[hippaisland]

Have a 2015 Merc 90 CT. Have noticed it doesn’t get the same RPM’s it used to when new. Same pitch prop. Runs great. I’m wondering if maybe the throttle cable is just a bit stretched and needs tightening. Any thoughts? Don’t need or do run wide open but nice to open it up every once in awhile.

 

[noluck]

it is possible, more likely a restriction in the fuel system or even lower fuel pressure

 

[trophywife]

tight turn in the fuel line can cause a vacuum collapse.
change your fuel filter? the one on the motor. they can plug and collapse too.
i chased a problem like this on my honda and all it turned out to be was a factory bend in a fuel line sucking flat.
try a different fuel supply set up straight to the motor for test run. process of elimination.

 

[gunnerlove]

If you are not getting the same rpms at WOT determining if you are in fact getting WOT 6 years later is a brilliant place to start.

 

[profisher]

Not always the motor can be water logged foam, transom, deck...any wood making the boat much heavier.

 

[hippaisland]

Not always the motor can be water logged foam, transom, deck...any wood making the boat much heavier.

Aluminum BV and no water in hull. I myself have gained a few lb’s however since owning the boat. Maybe that’s my problem. Will try running direct off jerry can to start. Thanks for advice!

 

[hippaisland]

tight turn in the fuel line can cause a vacuum collapse.
change your fuel filter? the one on the motor. they can plug and collapse too.
i chased a problem like this on my honda and all it turned out to be was a factory bend in a fuel line sucking flat.
try a different fuel supply set up straight to the motor for test run. process of elimination.

Will try new filter also. Thanks.

 

[grayclan]

Had the same problem with a Honda EFI. Turned out it was High pressure filter that wasn’t obvious. Cleaned it and ordered a new one. New one was green older one black. Turned out previous owner used ethanol and it broke down the inside of the fuel line. It bypassed the first filter and gummed up the the high pressure. Changed fuel line, added a additional filter. So far Ok.

 

[trophywife]

Not always the motor can be water logged foam, transom, deck...any wood making the boat much heavier.

even the cursed micro barneys.