engine sputter

[danielwiebe]

have an 02 21v seems to do this worse when firty put in the water when driving and then put directly into neutral the rpms drop it seems to almost stall but then comes right back. boat runs fine does it when warm but not as bad, but when you decelerate and you ease into neutral really slowly it doesnt do it. it idles great also
any ideas
thanks
dan

[danielwiebe]

Please any info would be great
Thanks

[TeamAllen]

Tell us a little more history on your boat.
When was the last time it was serviced?
Was it done by a dealer, independent shop or by yourself?
What was done?

[danielwiebe]

Started getting worse when cold and in just gear stalls at idle too. I smell fuel pretty strong at idle could I have a stuck injector or be running rich. How do I check without paying the dealer big bucks to scan it

[dogbert]

It sounds like you're not firing on all cylinders if you're smelling fuel. If your engine's a Mercruiser, you might check your distributor cap. It might need to be replaced.

[jsz]

I also have a 2002 merc 350 and used to have the same problem. I was getting a lot of black belt dust over the motor and it will get sucked into the IAC. Cleaning the IAC (idle air controler) with some throttle body cleaner fixed it.

I also got an IAC muffler($2, looks like a tiny sponge)to put in the throttle body to prevent the dust from clogging the IAC again.

[ajholt7]

I also have a 2002 merc 350 and used to have the same problem. I was getting a lot of black belt dust over the motor and it will get sucked into the IAC. Cleaning the IAC (idle air controler) with some throttle body cleaner fixed it.

I also got an IAC muffler($2, looks like a tiny sponge)to put in the throttle body to prevent the dust from clogging the IAC again.

Why were you getting belt dust? I would be looking into that. Misaligned pulleys or rotten belt. Gotta treat the root cause not the side effects.

[jsz]

I've asked the Tige mechanic and my local mechanic and they both said some dust is normal for that motor. I asked about the belt allignment and they said the dust would be much worse if it was out of allignment.

[boatwakes]

The IAC is a possibility, but if it doesnt solve the problem I've seen several Merc's with that same symptoms due to an improperly reading Coolant Temp Sensor which will tell the computer the engine is still cold and over fuel it to help it warm up. The sensor will not throw a code because technically it's still within proper range. If the problem continues, can you give me your engine serial number? I'll be able to guide you through the checks and sensor fail-safes to get the problem solved. Good luck!