75 Opti issues

[aarchdale]

2008 Optimax Serial # 1B556495. Hey guys needing a starting point on what to look for. Today the motor was running great for most the day, we stopped to fish and then fired up to move again. The motor would idle just fine but when i put it in gear it had no go, at full throttle it was just lugging real bad and couldnt go over 5 mph. And sometimes when i put it in gear it would just die. Never had any alarms go off or anything, just running great one minute and then falls on its face the next. Could it be in guardian mode? If i take it to a Merc dealer can their computer diagnose this? Any help is appreciated

[JOE54]

they should be able to depends on whos looking, check spark on all 3 also

[aarchdale]

I have good spark. What would the symptoms be if the diaphragm in the air regulator is bad? Mine isnt ripped but looks pretty bad around the edge

[JOE54]

very low or no air psi , likely wouldn't even start and then die, air escaping through cover hole

[aarchdale]

here is a pic of it. Looks like these arent easy to come by either.

THis is all i can find https://www.ebay.com/itm/NIB-Mercury...RYSWSH&vxp=mtr

[JOE54]

yea that don't look good,hope you got spec tool to reassemble ?????

[aarchdale]

yep, i got one, impossible without. IT will be a week before i get a chance to put it all back together. Ill post back with what happens

[JOE54]

[aarchdale]

Got everything back together and the middle cylinder still was dead. When i tested for spark i puled the plug out and grounded it on the block and i saw spark so i figured all was good. Well i ended up hooking and inline test light up and it barely put out a faint light, the other lit up very bright. IT ended up being a bad coil all along. Im sure the diaphragm was going to cause me issues soon, so im glad i replaced it.

[JOE54]