Hi, about a week ago I noticed my rpm is getting lower and lower with the throttle wide open. my top rpm use to be 5200, last week it only reached 4800, few days later it was at 3500 and two days ago its down to 3000rpm on wide open throttle. I figured it was fuel starvation cause on throttle wide open the primer bulbs get soft so I assumed its not getting enough fuel, so had my main fuel tank serviced and its clean with no clogged fuel lines. Any ideas on what else can cause this problem? Oh and Im running twin engines and both are suffering with the same problem.

Fyi engines have been serviced a few months ago so all filters and plugs are new. Someone said it may be a IAC Valve that may be messing up and if so, Whats that?
Please help!

If both engines are doing it usually is a fuel problem. Try running on portable gas tanks to eliminate the boat fuel system, and check fuel pressure.

__________________
Regards
Boats.net
Honda Outboard Parts

There could be many different problems with the engine, in my experience with working on the BF225 which is essentially the same engine minus the v-tec spool valve, I would start with the Idle Air Control Valve (IAC). This valve controls idle speed as it would in your car, at full throttle the valve is fully opened, to allow for more air to enter the intake manifold through the throttle body, when brought to idle it closes to an appropriate amount determined by your engine computer (ECM) only allowing enough air and fuel to stay at a consistent idle of 650rpm +/- 50rpm.

LOCATION:
MAKE SURE ENGINE STAYS OFF.
1. remove engine cover
2. stand in front of engine, facing the front of it
3. if you are familiar with what a throttle body is, look on the left side of it, it looks like a drum shape with wires coming from the back its a black plug.
4. if your not familiar with a throttle body, looking down you will see a black plastic air box, on it there are 2 inlets for air to get into the engine one on the left, one on the right. looking at the inlet on the left directly to the right of it there is a drum like device with a plug attatched, that is the IAC. it is held on by two 10mm bolts.
5. when you locate the IAC leave it plugged in, and remove the two bolts. once the bolts are removed, CARFULLY AND SLOWLY remove the IAC while still plugged in so you dont drop it in the water or more importantly rip the gasket, you want to be able to re-use it.
6. You will see a screen in the middle of it, odds are it is probably dirty (black and sooty). To clean the screen unplugg the IAC and use a brake cleaner, or Carb cleaner and spray directly into the screen. Make sure you have a bucked under it so you dont spill all of the toxic solvents.
7. Install back on the engine, and plug it in.
8. Start engine and try it out.

Let me know if this works for you. I have a few more ideas that may help if you are still having problems

Also you mentioned the engines were serviced a few months ago, what exactly did they perform as a service? This may help me help you.

Great will try that before I start ordering parts. I'll do that this weekend. Thanks
As for the service it was change oil , spark plug cleaning and the replacement of some fuel strainers in the engine, thats all.