Mercruiser 6.2 not in synch

brandonmayberry

My new 2002 Rinker 342 with the 6.2 engines does not show in synch. It is my first twin engine boat so im still learning. I have read that you should rely more on the synch gauge than the tachs however the synch gauge always shows pegged out to the starboard side. To get the needle on the synch gauge to even read halfway between middle and starboard it has to have the port engine full throttle and starboard in neutral.

However there was one day it did work properly and the RPM's were both reading the same and the synch gauge was in the middle. I have been running off of sound and the RPM gauges which have seemed pretty accurate, but on sunday last weekend while coming back to the dock one engine was showing a much higher RPM reading.

Im thinking it may have been just a screwy gauge and itll be better this weekend but just want to get an opinion on the issue.

Should i replace my synch gauge?
Should i look into replacing both RPM gauges?
Should i just ignore it and run by ear?

jme097

Definitely sounds like a gauge issue but I am sure @Alswagg will chime in. 

frenchship

Those Faria gauges are not reliable, I send mine in twice for repair still did not work properly.
The said that the have a lifetime warranty but they make you pay a certain amount for repair and shipping. They are not call tap gauge for nothing.I replace mine with a dual tach from
Flowscan that has a sync gauge incorporated it gets the engines sync within 50 RPM.

Michael T

I think the problem is gauges. I would rely more on RPM readings than a sync reading. If one engine was half the rpm of the other you should feel the uneven pull (push).

NavyCTRC

brandon,

my sync gauge doesn't work, just get the engines close using RPM, then fine tune by ear.  once they are in perfect sync there is a noticeable drone sound

brandonmayberry

thanks for the responses guys,

what i have been doing, is just getting close by RPM and then using my ear. I am just rather particular about things being right and them always reading differently and fluctuating messes with my OCD.

I have thought about going to a vessel view but dont know if my engines are compatible and the cost/difficulty to hook them up.

Any insight on that?

LaRea

It sounds like typical Faria gauge crappyness.  I'd open the helm and check the tachs and sync for loose cable connections.  Unplug and replug.  Gently flick the "# cylinders" switches on the tachs a few times.  

Usually, the sync is accurate even when the tachs are flakey.  

For an '02, you'd have to call Merc and give them the engine serial numbers to check SmareCraft compatibility.  Most few '02s are not compatible.

youstolemybeer

a few years back I lived on a 28ft Carver Mariner,.  twin 302 with v drives. It had the syn gauge.   As I watched the sync gauge match, the boat would act all screwy, and would be a bear to drive. I would actually have to work at driving the boat if I paid attention to the sync gauge. I tuned up both engines, rebuilt both carbs, had both props cleaned and polished. I ended up fixing the problem with a pair of wire cutters and got rid of the dang gauge.    
Listen to the engines, it will take you a few times out to hear the difference in rpm and trim but after a while you will be able to make the boat dance