Question about guagesinstruments

"Have twin 1986 270 crusaders

"Have twin 1986 270 crusaders in a 338 Chris Craft. The tachs inside are way off, and the flybridge tachs are not much better, but seem to be somewhat more accurate. Because these are old engines and use many different senders for information, what is my best course of action if I want accurate engine information inside? Replace senders and run the wires, or should I completely replace the instrument banks as well?

I just purchased this boat so do not know the history of the tachs/instruments, just know the inside tachs are off, as are some other instruments. I like the idea of one multi-function instrument, but don't know about the compatability. New instrument banks (4 or 6) I can find fairly cheap, but what about longevity? These engines have low hours (about 500hrs each) so I would like to tackle this job once, and have good engine info available. I did read about the tach switches on the back, and how moving the postition of the switch has helped.

I know the tachs are not driven with the distributors. Any suggestions or advice would be much appreciated."

"Not sure you can do anything

"Not sure you can do anything about calibrating a tach, other than making good connections (unless yours have a pot on the back that allows recalibrating). You might have to replace them all to get everything agreeing.

When you consider the pounding and moisture that electronic marine stuff is subjected to, they do pretty well.

Jeff"

"If you have instruments at bo

"If you have instruments at both stations, make sure you get the correct sender units. Tach are the exception. I've found it best practice to get the same brand of tachs at both stations - some mixes work well and some don't.

On the combined gauges, suggest you visit a shop that has them and judge for yourself if they are legible for your install. Nothing worse than spending money on something you can't read.

As far as new stuff or fix what is there - you'll have to inspect what is there, assess its condition, and bounce that off your budget. If you find any wiring that is suspect, probably better off to do the whole thing as the rest won't be far behind. If you opt to fix what is there, make sure you get the correct replacements as not all makers use the same 'standards'."

"I dealt with this issue for

"I dealt with this issue for 3 1/2 years until TODAY... I am heading to the boat, new dash and instruments plus 9 spools of wire in hand.
You may feel more comfortable getting an optical tach ( cheap) and a IR temp gun ( also cheap) and just keep checking things until you ultimately get the plan together."

""I know the tachs are not

""I know the tachs are not driven with the distributors."
I'd be surprised if that is true. Most every gas boat engine drives the tachs using the point signal (from the dist.). On some electronic systems, they use the pickup signal. Using a rotary sender like old diesels is almost unheard of for gassers.

In any case, the option I took is I trashed my analog tachs and put in floscan 7000's. Kinda pricy to get two, but eliminates inaccuracy, the sync gauge, and adds fuel flow and totalizers. You might just do this at the more used helm location, and leave a decent pair of analog gauges at the other."

"Thank you very much guys. you

"Thank you very much guys. you have given me great info with which to move forward. Enjoying my boat, and have taken all the teak off to work on it this winter. I know I need totackle the instrument problem, most likely this coming spring. Thanks again for the advice. Great website!"