New member '98 z280 7.4 bravo 3.
 

Hello to all. Just picked up this little Gem with only 250 hours. Runs great, no major problems, little tlc needed but easily handled.. couple questions...
Where can I get a schematic for the boat?
Also my tach bounces around under power and at idle occasionally, also if you tap it... Checked all the grounds, nice and tight.... Did find a brown wire with a factory soldiered washer coming off the harness that plugs into the back of the tach... Could that be the culprit, and if so where does it get attached? Mostly if I could get a schematic, man that would be great! Thanks in advance.
-Mike

Re: New member '98 z280 7.4 bravo 3.
 

Congrats on your purchase. I have the same boat. There is no schematic for the entire boat however there is a schematic for the engine related circuits including the instrumentation in the Mercruiser manuals. The problem with your tach is the 4, 6,8 cylinder selection switch on the back of the tach. Using a small screw driver rotate it back and forth to clean the contacts on the PCB. Make sure you put it back in the 8 cylinder position when you are done. If that doesn't fix it let me know as I have a more intrusive but guaranteed method to fix it once and for all.

Sent from my XT1254 using Tapatalk

Re: New member '98 z280 7.4 bravo 3.
 

Thanks Steve, I won't be able to try it today, but later this evening. I'll get back to you thanks.!!