What else could go wrong

BMILLER · Post by **BMILLER** » Fri Jun 15, 2012 6:13 pm

Went to work on the F28 and its idle issue on the starboard engine. So as usual I have to full throttle to set the choke and then set it about 1/3. Engine fires at fast idle, and I back it down some. Only now I have a nasty knocking noise that gets louder the lower the RPM.

. I get a long rod, hold it to my ear and isolate the noise to the tranny flywheel (back) area of the engine. The engine is idling irregular. The knock almost sound like/feels like if you have a stick shift car in too high of a gear for the rpm. Oil levels are fine and clean. Is it becasue when I pull back the throttle, it tries to idle dead slow? Ordering a tach/dwell meter to try to establish exactly what rpm this thing is running inasmuch as my tach are unreliable. Any ideas appreciated. Patience and $$$ are running thin. All these issues arose in the slip during my renovating.

prowlersfish · Post by **prowlersfish** » Fri Jun 15, 2012 6:40 pm

When you put it in gear will it change ? how abaut in gear when you rase the rpm ? If the engine is missing and you have some play in the plate on the flywheel it can make noise .

BMILLER · Post by **BMILLER** » Fri Jun 15, 2012 11:31 pm

By myself, I can't tell. My exhaust is too loud in the fully covered slip. I'm not comfortable leaving the helm with it running and in gear. Gun shy I guess. When I throttle it ALL the way back, it sorta sounds like an old hit and miss engine. Everything was normal until I started having the initial start up and idle issues..........now this. And I finally installed all the new bilge pumps, LED running lights, etc. My bad for thinking I may actually get to take her out.

rossjo · Post by **rossjo** » Sat Jun 16, 2012 5:54 am

Run it in gear in the slip

DOUBLE R · Post by **DOUBLE R** » Sat Jun 16, 2012 7:46 am

Have you checked the timing?

rbcool · Post by **rbcool** » Sat Jun 16, 2012 8:39 am

DOUBLE R wrote:Have you checked the timing?

+1
I've also seen a fouled fuel filter cause these exact symtoms

Ron

BMILLER · Post by **BMILLER** » Sat Jun 16, 2012 9:46 am

It almost sounds like it jumped time. I checked the distributor, its tight. The boat hasn't left the slip in almost a year now, only had it to idle just to keep moving the fluids around internally. Maybe it just needs to get out and get a decent run. If it is timing, wonder why it would have changed? Although, the PO did have issues starting this one engine. Perhaps he was playing around and messed it up.......he did to everything else. Hmmm.....a plug wire installed on a wrong cylinder...........? The starboard engine just doesn't start with the same authority as the port. It fires instantly and sounds totally different, almost like a high compression rod motor. Don't know... have to get this remote tach and see if I can get it to idle at around 700/800 in neutral for starters.

rossjo · Post by **rossjo** » Sat Jun 16, 2012 10:53 am

A backfire could cause it to jump time ...