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Can I make this old school tach work on my 1988 V4 Crossflow?

P

PhilSch

Regular Contributor
Freshly rebuilt motor started readily but it is idling too high, somewhere around 2K RPM's (estimate) on the muffs. The tach on the boat is not working correctly, showing 6K, bouncing down to 4K intermittently.

I understand idle speed is supposed to be set on the water, in gear and I will do that later but I want to do the entire timing/carb synch procedure and get the idle speed in the ballpark as well. About what RPM should I set it to when idling in neutral on muffs to be close?

Is it possible to hook up an old school dwell/tach to this motor? I have attached an image of a Penske/Sears Dwell Tachometer. If this old meter won't work can anyone suggest a reasonably priced alternative? Not to replace the boat tach but to use for tuneup procedures.

Of course I also want to fix the tach on the boat. Is there a way to determine if the guage is bad vs. some kind of wiring issue?
 

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No, the dwell/tach won't work on your motor. As for the boat tach, it might just have a loose wires problem or something like that. Worth taking a good look anyway. Also, make sure the switch on the back is set to 6.
 
Neat old dwell tach. Sell on eBay....might get a few bucks......unless you have some old "points" motors around. This, of course, measures electric pulses at the spark coil and for a four stroke motor.....so one pulse per two revolutions, then factoring in for you number of cylinders. For a single or twin cylinder you just figure the math.
 
I have a V6 ocean runner. Out of the water i set the idle to about 1100-1200. In the water it will drop. I believe the v4 should be right around 1000 out of the water. Meaning it’ll drop somewhere around 800 in the water.

Anytime I have a new motor I’m not familiar with I set the idle a little higher out of the water just to make sure I’m not stalling at dock and holding everyone up. Drive it somewhere and then set it to where You want it.

When I cold start my engine out of the water the rpms will be high around 1800. Once it warms up it drops down.

Piece of advice, bcuz I’m assuming you just got this motor. Make sure both thermostats are working properly.
 
johnson100 said:
I have a V6 ocean runner. Out of the water i set the idle to about 1100-1200. In the water it will drop. I believe the v4 should be right around 1000 out of the water. Meaning it’ll drop somewhere around 800 in the water.

Anytime I have a new motor I’m not familiar with I set the idle a little higher out of the water just to make sure I’m not stalling at dock and holding everyone up. Drive it somewhere and then set it to where You want it.


When I cold start my engine out of the water the rpms will be high around 1800. Once it warms up it drops down.

Piece of advice, bcuz I’m assuming you just got this motor. Make sure both thermostats are working properly.
Click to expand...


Thanks for the tips...
Phil
 
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