need help 225hp honda lossing power

[aristakat]

need help lossing power on high rpm over 4200 on port motor, it misses and losses power intermittent though ran second half of trip yesterday back in 20 miles high rpm and ran fine any ideas?
heres where we are
1. changed racor filters on fuel
2. checked oil fine
3. plugs changed 100 hrs ago
4. checked fuel bulb when running and sounding low rpm nothing changed when squeezed checked it to other motor same
5. I checked a inline filter near fuel bowl a year back and it was clear back then so I have never replaced that so I might look there
6. had one mechanic guy who though miss was a timing belt slipping, I then call honda dealership/service and they said if timing belt would be very noticeable high and low rpms plus belt is notched so more then likely not this
7. starboard motor runs fine and is on a seperate fuel tank motors 1020 hrs on them.
8. I have shop manual

 

[chawk_man]

I assume not fault lights or alarms, since you did not mention any.

It's highly unlikely you have a timing belt problem, based on your description.

Easy things first. Check/drain onboard fuel-water separator. Drain and clean low pressure fuel filter. Drain the VST (observe if any gunk or water comes out) and drain/clean the high pressure fuel filter - replace if necessary.

If that does not cure the problem, then start investigating the plugs, coils and wires to the plugs. Pull each plug and look for fouling. Check connection plugs to coil and clean if there is any corrosion.

 

[aristakat]

its funny you stated this I just drained low pressure fuel filter and plan on replacing it tommorrow. I already just changed racor filters last week with water seperators so we are good there. going to go ahead and change high pressure filter also looks like I have to spilt cowling to get to that one I think? what is vst do and where to you drain that ?
I think its vapor seperator '''''''

 

[chawk_man]

The Vapor Separator Tank is in place to assure an adequate amount of non-turbulent fuel is available to the high pressure fuel pump. (The fuel in the VST tank is kept under pressure to prevent vaporization, thus preventing the fuel from becoming too lean under variable demand.) On the back starboard side of your motor, you will see a plastic tube looped around a holder. Unhook it, and look down at the base where it connects. Beside the connection is a small set screw. Use a long flat blade screwdriver to open the set screw - slowly. With the end of the hose extended downward into a clear container that will hold at least a quart of liquid, start opening the set screw. Do not open too far - if it comes out, you will need to remove the lower cowling to retrieve it. Anywhere from two to three pints of gas, and maybe some water and gunk will come out of that tube. Be patient, the last stuff to come out is usually slow, but drain out as much as you can. If there is water, or any gunk, then your fuel-water separator and low pressure fuel filter have failed and need to be replaced. At that point, you should also change out the high pressure filter which sits on top of the fuel pump and is held in place with three 5 mm screws. If you are still having problems, then it may be necessary to remove the VST and clean it out and clean the screen on the outflow tube.

 

[aristakat]

we'll I think I found my problem , honda manual states to change hp fuel filter every 200 hrs . OOPS I never have changed them 1040 hrs ouch...
I changed filters on both motors as well as lp filters also. I feel very lucky never got stranded due to this. The bright green filter obviously is the new one, the one that is smooshed sort of is the one from port motor that I have had problems with at high RPM. I have yet to water test motors other then hose start .... Hope ALL learn from my mistake and change them filters pretty easy to do just had to pull starboard side of lower cowling... thanks again for help once again Honda service Manual helped BIG TIME

 

[chawk_man]

Holy Crap - they're some bad looking filters! I'm surprised you ran that long with them. Hope you cleaned out the VST while you were in there.

Glad you found the problem.