'09 292 Engines out of synch
 

I'm posting this here first and then may move to general depending upon the response.

I have a 2009 292 with about 50 hours on it. Just recently, the engines started running at different rpm's when throttles at same position.... about 500-600 rpm different when in higher rpm's. Not a big deal as I can adjust the sticks so that both running at same rpm. Or is this something I need to look further into?

Also, the starboard engine which is always the lower rpm side will only spin up to 4500 rpm at full throttle. This has me more concerned than being in synch but I'm thinking it may be related. Is there anything I can check before taking back to the dealer? I'm not a fan of being without my boat for a couple weeks while they look at.

Thanks in advance for any input.

Unless it is a bent prop, you need to take it in and have it checked out while it is still under warranty. Could be minor or serious.

Maybe a fuel filter also.

I would say there is something wrong beside a throttle adjustment if you are expierencing a loss of RPM's at the top as well. Jeffman hs led you to the first place to look. The prop. Any vibration while running? If not, then a check of the fuel filter is a good next step. From there, ignition, spark plugs, wires... Then to the dealer!

Let us know how you make out.

Dave

Unless you've seen a huge loss in top speed, look for bad alternator diodes in the engine that reads low. Been there/done that....

No vibration while running that I can detect. Some while accelerating in the 1500-2000 rpm range... always thought cavitation of some amount and getting up on plane. Prop doesn't appear bent to me. How bent would he have to be to cause a problem? I did run through shallow area on the lake one time (noticed some muddy water surfacing behind so I trimmed up a little and was fine) and had a nick on the prop that I took a hand file to, but only because I was being anal about little bur on the edge. Could something as minor as that cause a problem? It was not something hard or feel a clunk.... I'm guessing just some rocks/pebbles in the lake bottom that caused it.

Could any adjustment be causing the throttle to not push forward enough to just not let the engine keep rev higher?

Thanks again everyone.

Take off the flame arrestor (three small nuts) and see if the throttle body butterfly is opening fully. Should be straight up and down with the throttle wide open.

500-600 rpm is a significant loss. From your description, it doesn't sound like it is a prop issue. You probably should take it to the dealer for them to check it out. Hey, at least it is under warranty!:drink:

The motor that has dropped RPM may be running on 7 cylinders. Check the plug wires and spark plugs. It is hard to tell by ear if the motor is missing.

Is the speed actually down (5-6 mph), or does the tach just read low? If the speed hasn't fallen off, you have a gauge problem, not an engine problem.

When the diodes go bad in an alternator, they allow alternating current into the 12vdc system. This creates havoc with things like gauges.

Top speed is down... or atleast I think so. Past weekend in relatively calm waters with just me and half tank of gas, 64 was about the best I could get. I know I have been in upper 60's if not 70 before so I think that speed is down and not just a gauge problem. But I will keep that in mind.

I will check the throttle body butterflies, fuel filters and wires/plus this weekend. I'm just hoping it's not something to have to take into the dealer knowing it is usually 2-3 weeks before I get it back.

I had a drop in rpm (400) and top speed in my boat last year. Felt more sluggish out of the hole. By ear, nothing sounded amiss. Did a little investigating in the engine compartment and the number 2 plug wire was hanging down in the bilge. Hopefully your problem is as easy to resolve as mine was. Good luck.

kfvintx...you are going to die (well not really), but you now have the 5th or 6th Formula that has the SAME exact problem. I can't say it is a Formula issue, and I can say that since I own a Formula as well, I have the SAME issue. Below is my issue: The similarity is all MERC engines and Bravo III Drives. Is that what you have?

2008 Twin 496Mag with Bravo IIII Drives.

I maintain pretty detailed records of fuel burn, GPH, MPH, RPM, etc. I have the factory installed "mechanical RPM" gauges and then two smartcraft monitors directly connected to the engine. I went on a 80 mile trip this weekend. On the way out everything was perfect...that means when I throttle up my engines, I would bring the lever's up together...and always my engines run about the same RPM on cruise, burn about the same GPH and stay in "sync".

On the trip home, we departed the marina...all was well...ran about 5 miles, then anchored out for an afternoon swim. As we left, I started out and all of a sudden my STBD engine is about 200-300 RPM's behind my Port at the same "throttle input". Makes no sense, so I think I have seaweed or something on my props...so I stop, everthing is perfect...much be my imagination.

Start up again, same thing...STBD engine needs about "1 1/2 inches" more throttle input to maintain the same rpm's as the Port engine...both gauges read this way. So I think maybe something slipped in throttle linkage...NOPE, at least not that I can tell...at the engine both throttles seem to advance exactly the same distance.

Now it gets worse...so I then end up cruising this way...meaning I have way more throttle into the STBD engine to keep the RPM's the same...and guess what, I am not burning a TON more fuel in my STBD engine...however they are now the same exact RPM. (A ton more fuel means 2 GPH, but for my boat that is way off.)

So now I think somehow my gauges are messed up? How could the fuel burn be so different. And of course, when I got back....my STBD engine did burn more fuel on the way home, vs on the way there when they both burned the same.

Any ideas...where to look first. I find it hard to believe my factory tach and smartcraft tach went at the same time. Or do they feed of the some comon point, such as the ECM, even though they are connected in different ways.

OH, I also checked the trim, they both seeem to be trimmed the same and both props show no damage.

Thanks in advance for some more ideas..

I was also wondering if we should post this in the Techical sections instead...maybe it is not a Formula issue and others can help out? Not sure how cross posting works in this forum though? Any thoughts?

I also compiled a list of other people having similar issues (not just forumula). Any of these items could result is issues...and other people had success at some point or another by resolving these issues.

Ground cable to battery loose
Spark Plug(s) Bad
Spark Wire Disconnected
Fuel Filter
Too much oil
engine in Guardian mode
Crankshaft position code activated
camshaft position code activated
Clear all engine codes