'88 Force 125 idle dies very slowly

['88 Crew]

So I have worked on this outboard for the past couple months and it has gotten me reliably on the water about 20-30 times. The only thing that I have noticed is that as soon as I crank it up, the idle is normal (approx 700-800 rpm in gear) but after I run it all day (starting and stopping at various locations over about 5 hrs) the idle rpm drops to about 600-700 without any rhyme or reason. It then almost boggs down and it doesnt idle nicely anymore. Before I take it out the next time, I do the once over on the engine and make sure that all bolts are tightened and everything looks as it should, and then start it up in the driveway. This engine has a rough idle, I know, but it does seem to vibrate quite a lot when in specific rpm zones. Is this also typical? I know this is not a major conceern but I am still wondering why this could be happening. Possibly a carb-retune is necessary? Any ideas or thoughts are appreciated.

 

[jerryjerry05]

First thing is a compression test and then a spark check on all 4 cyl.
Then do the starting fluid spray test.
Start motor and then spray SF all around the intake side.
That's the stbd. side where the electronics are mounted.
If the spray makes any difference? then it's sucking air somewhere??/
One tiny backfire can blow the port cover gaskets.

ANY??? blow back from the front of the carbs?? That would indicate reeds.

Top 4 posts in this section have tips and tricks for the Force/Chrysler motors.
Find the post by FrankA and do the linc and sinc described there.
Read the rest, there might be something there you can use?

 

[Jiggz]

Does it seem to idle better with the top cover off? If so you might have some exhaust leaks coming either from the exhaust relief hose or from the adapter plate on the midleg. But you still need to do what Jerry said especially the compression just to be sure.