Indmar 340 cat cold idle hunting

[DOCDRS]

Like the title says. Cold idle moves up and down on cold start up. Prob between say 7 and 900 rpms for instance. If I head out it will continue this hunting up until about 1700 rpms , around 2200 it will stop the hunting and smooth out. Once the coolant temp is up to 160 all this goes away and I have a very smooth 600 rpm idle with no more hunting ( the rpms are not exacts but close examples)
It seems to be getting a little worse.
I'm going to remove and clean the air filter and remove and clean the Throttlebody and inspect the maf.
Just wondering if anyone else has experienced this and what did you do ?

[mmandley]

I have noticed a little hunting at idle when we first leave the dock and are headed out of the cove.

But as soon as the engine warms up it stops.

I would agree your MAF could be the issue, but the difficult thing for me is the inconsistency of mine. This week we actually went out 5 days straight. Only the very first day it surged a little. After that not all weekend. I only notice it when the boat sits for a few days.

I am not sure if your boat has this but IAC (Idle Air Control) if those get dirty it will exhibit surging.

[DOCDRS]

Well , I have yet to do anything and boat cold idled fine this weekend. So now , Im thinking it could be a dirty fuel injector from poor fuel since it went away. Going to try some seafoam, and will clean the TB later when I get time