|Posted: September 09 2009 at 19:02 | IP Logged
Trying to figure out where a gas odor we smelled and the vibration originatd from. We had just left the dock and we were going slow in a 5 MPH area for approx 15 minutes, all seemed fine. Then I smelled a strong odor of gas. I figured maybe because of going slow for such a long periiod of time. I then started to bring it up to plane, but I had to really bring it up to a lot higher RPM, more then usual, 4200RPM. Trimmed it out and once on plane I brought it back down to 32000-33000RPM (usually my cruise range at 24-26MPH). Now its was going a lot slower then normal (18-20 MPH) and I was feeling a slight vibration. It was also starting to fall off the plane.
I stopped then to investigate further. I have no carb, its a 7.4L fuel injected engine. I opened the hatch and I really did not smell the gas like I did with the hatch closed. The gas odor was not quite as bad now. Could I have gotten some raw fuel mixed into the exhaust somehow, and smelled it there becuase I was running slow? Did the raw fuel load up in the engine somehow? I ran with the hatch open to hear the engine better, and about 3000 to 3300 RPM and now I was getting a bad vibration, which I never had before. Why would I get this vibration?
Here's my thought, does this fly?
Sounds to me like something happened in where gas was not getting to where it should have been (causing the odor) If not getting to the cylinders ( maybe due to the vacum noise) could this also be the reason for the vibration and the decrease in speed? (If 1-2 or 3 cylinders were not firing because of less then normal or no gas). If this does not fly what are my scenarios to look at? Where are other areas that I might have been getting the odor of gas and vibration from?
Some other factors were:
The boat seemed to run a lot slower then normal. There was a lot of vibration, and a loud vacum noise. Now I know the 7.4L engines have a whistle to them, however this was not a whistle it sounded more like a vacum leak and it was a least twice the volume of the inherint whistle the engine normally has.
Ciera Sunbridge 2855
7.4L Bravo III (Duo Props)