671tib lost rpms

[captcrunch]

Boat ran great until went to go shark fishing today, couldn't get above 2000 rpm, changed fuel filters no difference. Anyone ha e any suggestions what to look for next

 

[racclarkson@gmail.com]

Boat ran great until went to go shark fishing today, couldn't get above 2000 rpm, changed fuel filters no difference. Anyone ha e any suggestions what to look for next

Bottom?

 

[captcrunch]

Bottom was done maybe 6 weeks ago boat ran great last week for offshore tuna fishing

 

[racclarkson@gmail.com]

Bottom was done maybe 6 weeks ago boat ran great last week for offshore tuna fishing

Depending on where you’re located, warming water temperatures and condition of paint, six weeks can be a long time. How about growth on the props? Dirty props can be 80% of the drag on my boat, for ey. I think you have to eliminate the bottom if nothing sticks out on motors.

 

[jim rosenthal]

Both engines or just one? Both sounds like the bottom, growth on the wheels, or a combination. One could be a fuel issue or something wrapped around a shaft, perhaps.

 

[Pascal]

After the filters (secondaries too?) I d check the wheels. Doesn’t take much barnacle growth to affect performance. Don’t know where you are but down here on FL 6 weeks will do it. Usually something wrapped on a prop would cause a vibration but not always

Any smoke on start up, underway? Any sheen on the water ?

Doesn’t have to be both engines. One weak engines could prevent the other from reaching full RPM

 

[captcrunch]

In New York, no smoke, props were reconded while bottom was done. Will do the secondaries and hopefully just picked up some Crap in fuel and that fixes it

 

[Pascal]

How old are the secondaries? I replace both primaries and secondaries at every oil change, mains and gens

Take a look at props any way... if in reasonably clear but cold water you can attach a GoPro to a boat hook and take a look

 

[JD5652]

I would also check your air filters and turbos... turbo should spin very freely when you give it a whirl and continue spinning for a few seconds....

One other VERY remote possibility... but would take a very easy check... make sure the emergency air flapper shutdown is not inadvertently closed...

 

[captcrunch]

Secondaries were changed last year. I’ll change them again and clean air filters just in case

 

[Pascal]

Last year maybe ok but how many hours since?

 

[Dan Mapes]

Make sure the shut down levers are fully seated by the springs. Yes, that happened to me. The booster spring on our port engine would drag the throttle back so I loosened that up also.

 

[captcrunch]

Not that many hours at all maybe 30

 

[captcrunch]

Improvement after changing secondaries, one air filter seems to be full of oil as I took them off to clean and one keeps dripping oil anyone know what this could be?

 

[racclarkson@gmail.com]

Secondaries were changed last year. I’ll change them again and clean air filters just in case

Bottom

 

[JD5652]

In general.... if the filter is full of oil and the turbo spins freely.... meaning no oil/grease breakdown from bearing, etc.... it could simply be in need of cleaning if it hasn't been done for a while.... You have Walker Air Seps... or somehting else? If Walker Air Seps…. then you actually put oil on those filters to make them more efficient at air filtration...

 

[racclarkson@gmail.com]

Improvement after changing secondaries, one air filter seems to be full of oil as I took them off to clean and one keeps dripping oil anyone know what this could be?

Excessive blow by or stopped up filter drain hose (Air Sep) and/or its check valve. Need to verify turbo drain is open as well.

 

[captcrunch]

Has a set of k and n filters right off turbo. Pouring here in ny today but hopefully will bayvtest tomorrow and all will be ok

 

[captcrunch]

Boat still not exactly right, will not run 100% but then will feel like it should on its own then bog down a little

 

[Boatsb]

Airseps have a second filter many people dont change.