Jumpy Tach - Solution

Hey all:

I have a 2004 G3 HP180 running a VMax 150. Just this spring, the tach started acting jumpy and erratic. Tapping on the glass would get it to settle a bit until the next time. Had no idea what was going on until I trouble shot over the internet. Teleflex's website describes the issue as a "film" that forms between the Selector Switch contact and the circuit on the printed board. According to Teleflex, this film tends to intermittently insulate the two causing the strange readings. The suggested remedy is to rotate the switch about 6 times, resetting the switch to its original position. This is supposed to eliminate the film build up and return the tach to normal.

Want to report that I did this last weekend and today was the first time I was able to get out. Sure enough, the tach was acting perfectly fine. No jumpiness or erratic issues at all. Thought I'd pass this along to folks in case they have similar issues.

Jim

Can the mod make this a sticky at the top? Mine did that a couple of times last year but none this year. It just starting working properly, I did nothing to fix it.

GREAT TIP!!!!!!!!!!

My hp tach has been doing the exact same thing so I will give it a shot. http://www.bassboatcentral.com/smileys/thumbsup2.gif http://www.bassboatcentral.com/smileys/thumbsup2.gif http://www.bassboatcentral.com/smileys/thumbsup2.gif http://www.bassboatcentral.com/smileys/thumbsup2.gif

Thanks for the tip! Haven't had the problem but now I know what to do if it ever happens.

What prop are you running, Jim?

I want to say 23P, but I haven't look recently. Its whatever came standard on the 150 VMax in 2004. Runs well, but will admit that I had a bite problem yesterday after coming off plane. Had to let the water settle before I could power up again. Love the set up as it jumps right out of the hole and I get close to 60mph max on the GPS fairly regularly. Best ever was 64mph.

BTW, day 2 of running after the tach fix and the needle is rock solid. Looks like I got the jumpy needle fixed!! Thanks to Teleflex customer support for posting the fix. Oh, and I managed to jam the speedo. More loose wood in the river! Trick with the drill bit turned by hand (and a needle pick) worked again . . .

Can you describe what the selector switch is, and where it is? Mine doesn't have a problem, I was just wondering what these part names refer to, in case this does hasppen to mine.

On the back of the tach (you likely need to remove from the dash), you can see a dial with markings like "6P" and others around it. There will be a slot for a small flat head screwdriver. There is also a small raised arrow in front of the slot. That's the "selector switch" that is set for whatever type engine you have. If your tach is jumpy or acts erratically, but a tap (or two) on the glass fixes it or settles the tach needle AND your tach is several years old, chances are you have the dreaded "film" build up. Using a screwdriver to rotate the selector switch several times back to the original setting should resolve the issue. It did for me!

Thanks! That sounds simple enough.

The guage problem I have is my speedometer guage doesn't work, but I think it is because of a clog in the tubing somewhere in my lower unit. I can get to the end of the pitot tube with a drill bit, but it apparently makes a sharp turn upward, so the drill bit trick won't help past that point.

You might try disconnecting the tube where it connects at the lower unit before going into the hole and blowing it out.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Sigma &raquo;</TD></TR><TR><TD CLASS="quote">You might try disconnecting the tube where it connects at the lower unit before going into the hole and blowing it out.</TD></TR></TABLE>

Yep- tried that and that's how I got the problem localized. Air toward the guage from that point will move the guage needle. I'm just cautious about how much air pressure to put in the line going through the lower unit- if its a plastic or rubber line, I'm afraid I might rupture it before the blockage comes loose. Plus- its hard to get a good hook up to get a sealed flow of air into the line.

I have also done this: disconnect the tube as it comes out of the lower unit. Fill the tube with dish washing liquid and let it set for a couple of hours Put a hose nozzle against the disconnected tube and turn the hose on full pressure with a narrow stream on the nozzle. Out it came. Before I did this I inserted a tiny drill in my hand and spun it around a few times to extract wood fibers. I keep a tiny drill now mounted in a little block of wood to handle it more easily. BE CAREFUL NOT TO BREAK OFF THE TINY DRILL IN THE HOLE.