Yanmar 1 gm issue
I have a Yanmar 1 gm. I start it up in neutral and it starts just fine. If it's been a week or so, I need to hold the starter for maybe 10 seconds and then it catches. If it's been running that day, it catches within 1-2 seconds. Idles great, sounds good, doesn't smoke.
The problem I started having a week ago is when I put it in gear. When idling, I can throttle up and down and the RPMs go up and down as they should (idles at around 650 and tops out at about 3200). Then, I put it in forward, and then throttle up a bit. The RPMs start going up and then drop all the way back down to idle speed (~650 RPMs). After about 30 seconds, the RPMs come back up to match the amount of throttle I'm giving, and then the engine/throttle is in perfect sync for however long I run it for.
My intuition tells me it's not a fouled prop, because after about 30 seconds it runs exactly like it should.
What should I check? Obviously, my concern is to catch an issue before it becomes a bigger one. Right now, this doesn't affect the use of the engine.