tach question will not read over 3200? but motor sounds alot faster

[bigbenc2]

i have a 1986 glasstream 160v with a 50 hp rude mod# e50belcd ser# g1097910..my prop is a 15 pitch. top speed of the boat at is about 30 mph.<br />my tach is only reading 3200 and when it is at about 2500 it will have a spike every now and then where it will jump 500 rpms or so but the motor doesnt sound any diffrent.are there any ways to troubleshoot this?.....i took the tach out and looked and it is set on six....and all the wires were tight with no corrosion.<br /><br />any help would be great.<br />ben c.

 

[Steve135]

Re: tach question will not read over 3200? but motor sounds alot faster

bigbenc2 <br /> First question is did it ever read any higher and this just started happening? try the ground first, and then check to see if your battery is still charging could be your retifier is bad this would cause problems.

 

[bigbenc2]

Re: tach question will not read over 3200? but motor sounds alot faster

i just bought thi boat 3 months ago. and have nevet seen it any higher. do i just crank the motor and lay my meter on the batt.?

 

[bigbenc2]

Re: tach question will not read over 3200? but motor sounds alot faster

how much is a retifier?

 

[Walker]

Re: tach question will not read over 3200? but motor sounds alot faster

Some tachs have a switch on the back for 2, 4 or 6 cylinder. Check yours.

 

[bigbenc2]

Re: tach question will not read over 3200? but motor sounds alot faster

mine is set on 6

 

[bigbenc2]

Re: tach question will not read over 3200? but motor sounds alot faster

is that the correct setting

 

[Walker]

Re: tach question will not read over 3200? but motor sounds alot faster

No, set it on 2. Your motor is a 2 cylinder right.

 

[bigbenc2]

Re: tach question will not read over 3200? but motor sounds alot faster

yup a 2 cyl......i was wondering what those numbers were.....thank you

 

[bigbenc2]

Re: tach question will not read over 3200? but motor sounds alot faster

now i cant wait to see what it is realy reading!<br />iboats fourm is the best....thank you walker and stinky2

 

[bigbenc2]

Re: tach question will not read over 3200? but motor sounds alot faster

why do you think this was set on six? it is a factory guage,or i should say the one that come on the boat when it was new.

 

[Steve135]

Re: tach question will not read over 3200? but motor sounds alot faster

The numbers on the back of the tach I thought were for poles on the stator not cylinders. Note it says 2p 4p 6p, 6p would be the correct setting for your motor, as with most Johson/Evinrudes!

 

[Walker]

Re: tach question will not read over 3200? but motor sounds alot faster

Teleflex says your right Stinky. One old tach I have laying around has C's by all the numbers.

 

[bigbenc2]

Re: tach question will not read over 3200? but motor sounds alot faster

oh ok .....so i should start looking into the rectifier?

 

[Hooty]

Re: tach question will not read over 3200? but motor sounds alot faster

Don' know bb2. Usually, if it's the rectifier, the tach just quits working. Get a volt meter and check the battery voltage with the engine not running and at a high idle. If the voltage reads the same both ways, the rectifier's bad. If the voltage goes up at the high idle, the rectifier's okay. <br /><br />c/6<br />Hooty

 

[rickdb1boat]

Re: tach question will not read over 3200? but motor sounds alot faster

I'd be looking at the Tach being bad as your speed sounds right for your boat/motor combo. See if you can borrow one to verify if it's good or bad. Some marine shops have a shop tach they will lend you for this purpose... If you were really only getting to 3200 RPM's, you would be going considerably less than 30 MPH... Also, when you turn the key, does the Tach go to zero?

 

[Leopoldo]

Re: tach question will not read over 3200? but motor sounds alot faster

Originally posted by rickdb1boat:<br />Also, when you turn the key, does the Tach go to zero?

Heh Rick, good question and I would like to know the answer and the reasoning for any zero readings. Thanks in advance!

 

[bigbenc2]

Re: tach question will not read over 3200? but motor sounds alot faster

yes when i turn the key the tach will drop to zero...what does that mean?

 

[farginicehole]

Re: tach question will not read over 3200? but motor sounds alot faster

I'm just enabling my e-mail notification so I can follow this thread. I'm experiencing similiar problems to bigbenc2 with my tach.

 

[steviecops]

Re: tach question will not read over 3200? but motor sounds alot faster

What if the tach wasn't returning completely to zero? Would that mean the tach is faulty?