70 hours on remanufactured 150HP powerhead. When engine comes off fast idle the rpms will control drop to 400-500 rpms and stall when in the water. On the hose you can hear a distinct “blurping” sound from the exhaust hub.

Does not do this every time- sometimes it’ll settle in 700-800 rpms and be fine.

I can confirm I’m at 36psi constant at the fuel rail. Fuel pressure does not drop when rpms fall. Has new VST filter and pressure regulator basket filter. Low pressure pumps (2 of them) were new 70 hours ago.

I’ve sent the injectors out to be professionally cleaned and reinstalled- same problem.

Set TPS to .48 at idle and performed “link and sync” per service manual.

Can confirm compression is 135psi (or close to) on all cylinders.

O2 sensor is new 70 hours ago- I’ve removed it and cleaned to be sure. Sniffer tube was cleaned as well.

Has new spark plugs and thermostats.

Runs fine when on plane- problem seems to only exist at low rpm/idling.

Looking for anyone who has experience similar symptoms.

I will repost my finding when I repair.

Update 5/15/21
After adjusting the oiler arm the motor has been running fine. Used it 2x this season and have had no issues.