Tach issue on 1995 fastrike 175 hp

[RangerJim]

Tach is exhibiting some strange behavior! Last year the tach completely quit but I replaced the rectifier (1995 Fastrike 175hp) and that solved the problem. However, the last couple of weeks, the tach has been jumpy and erractic; bouncing from 4000 rpm to 6000-7000 rpm interminently. doesnt do it all the time, but often enough. Have done a search and looks like it could be the tach going bad or could be the rectifier? Any guidance on troubleshooting? thx


Modified by strat285XL at 3:47 AM 5/23/2011

[Bassmeister]

Try this, on the back of the tach is a pole selector. Mark where it's set now and rotate it back and forth and then set it back to where it was and see if that helps. If not check charging voltage while running on the muffs with voltage meter connected to posi and neg posts and verify that the rectifier is charging. Should read 13+ volts while running. If so, I would suspect tach.

[RangerJim]

First, sorry for the long post!!! Got the chance to do a little troubleshooting on my 1995 Fastrike 175 (Model No J175GLEOM) over the weekend in a effort to resolve this tach issue I am having and hoping that Seahorse, ChampionMan, or one of the other resident experts on OMC would be able to provide a clue on what is the issue.

First, checked the battery voltage at batt terminals, engine not running: approx 12.15 volts
Then checked battery voltage at the batt terminals, engine running around 1000 rpms: 12.17 volts . (Does not appear to be charging battery?) boat volt gauge seemed to read lower than usual on the lake today...

Next, I checked the voltage on the gray tach wire at the regulator/rectifier. I got 0 Volts with key on/not running and 5.45 volts with engine running at 1000 rpms.

Checked the stator charge coil resistance with the following results. between the Brown and Brown/Yellow wires and between the Brown/White and Brown/Black wires. Spec I found says normal range is 450 - 600 ohms. I measured mine at 583 ohms.

For the stator power coil resistance and the following results. between the Orange and Orange/Black wires. normal range is 50 - 60 ohms. I measured mine at 60 ohms.

Any ideas on what might be causing the erractic tach behavior and what appears to be an issue with the battery getting charged?

[ChampioNman]

The voltage regulator doesn't appear to be charging the battery. With the motor running you should be reading ~ 12.6 volts at idle and upwards of 13 volts at higher RPM's.

[RangerJim]

that was my assumption as well, on the lake yesterday and the boat volt meter would register low 12 volt range most of the time, though every now and then it would jump up to normal 13 volt range for a few secs. I installed a new regulator early last year from CDI electronics......I know, maybe I should have bought OEM!

[ChampioNman]

And I hope you don't have wing nuts on your cranking battery.

[RangerJim]

nope, got that hint on the lock nuts many years ago So odds are pretty good that I am looking at needing a new rectifier on the fastrike then based on conclusions so far?


Modified by strat285XL at 8:39 AM 5/23/2011

[ChampioNman]

If the tach is going crazy and the battery isn't charging then yep time for a new one.

[RangerJim]

Thank you, sir! No doubt that is the best website around.

[RangerJim]

just an update. replaced the rectifier and everything is working properly now. tach and charging. thanks! hopefully this will help someone else too.

[ChampioNman]