Blueghost924
Petty Officer 1st Class
- Joined
- Sep 19, 2013
- Messages
- 250
Hi - I have a 1982 Mercruiser 470 (the ol faithful 4 banger) with the 2 bbl carb. I've finished work on the exhaust, and started it up and ran it yesterday in the boat on the trailer at my house (not in the water). The sterndrive is not on. While I've been making maintenance repairs and replacing old parts, I've always started it up with the inboard cover off (to watch the engine). Yesterday, I had the engine purring at 1200 RPM and decided to put the inboard engine cover shell on while it was running. Immediately, the engine RPM dipped down a little bit and I could detect a difference in the way it was running. I believe I had to bump up the throttle a little to bring it back up to 1200 RPM. The only thing I could think is putting the hard top engine cover back on causes a change in air pressure going into the 2bbl carb. Does this make sense? Any tips, advice, etc... ? Again, this is all at the house on the boat trailer, not on the water.