Manual motor sync issue?

[gkuypers]

My brother in-law has a 2001 340 Amberjack and is having trouble lately with his 496 motors syncing. It's at the dealer and they changed the fuel pump on the starboard motor, but the port they said is fine. Even after doing this they still are not syncing and the boat shows no codes? Anyone have similar issues that might have an idea of what's going on? Thanks.

 

[dpmulvey]

What do you mean by synching?

 

[Do Over]

I'm sure you know they don't synch automatically.......so more info is necessary.

 

[Jimmy Buoy]

If by "not synching" you mean the engine won't hold a particular RPM for an extended length of time, I'd say change the spark plugs. I use "Accusynch" on my boat and it will automatically ensure that the slave engine's RPM's match the primary engine within 10-15 seconds, but it won't work miracles. If one or both engines aren't operating properly you will have an issue trying to sync.

 

[gkuypers]

Manual syncing, I mean when you get on plane and to cruising speed on both motors 1 motors Rpms will drop off. Then once you stop and re-plane they run fine for a while and then drop off again. Anyone who has experienced this knows the boat does not run very well when boat motors are not at the same Rpms. I thought he changed the plugs already but I'll ask.

 

[scoflaw]

Could be as simple as tightening the friction screw on your throttle control

 

[Paul Lambert]

I have an 89 Weekender twin 5.7 and to get the boat to go straight at low rpms , the engines will run at same rpm and synchro gage dead center. At higher RPMs I have to have Port engine say at 3000 rpm and the Star engine at will be at 2500 rpm to sync up. Why is that ?

 

[SCORPIO]

I have an 89 Weekender twin 5.7 and to get the boat to go straight at low rpms , the engines will run at same rpm and synchro gage dead center. At higher RPMs I have to have Port engine say at 3000 rpm and the Star engine at will be at 2500 rpm to sync up. Why is that ?

I suspect your tach is not accurate. Try turning the 4,6,8 switch on the back several times between settings, then return to 8
It cleanse the contacts a bit and improves accuracy.

 

[Paul Lambert]

Sweet thanks for the tip !