Tach setting for '81 70hp Johnson (poles)

[imported_beck]

Test ran 70 hp Johnson with the muffs. Well the kill switch works, I forgot to hook it up and it would not start. When I installed the lanyard it started right up. A few questions.

What pole setting for a '81 70 hp Johnson?

Also idle seems to be a little high. What is the best way to lower it?

I switched some parts from 2 control boxes I had to make one with a kill switch. I lubed the internal parts with a spray grease that feels like it may be too thick and wants to drag. When I raise the idle speed lever than lower it feels like it doesn't want to return to the lower speed.

One last question for now, I hear alot about the 3 cyl 70 hp being good engines, but then you hear about not getting the right fuel to all carbs and burning a pistion. How can I check to prevent that from happening ahead of time as not to ruin a fine running engine?

Thanks,
Beck d

ps: I just ordered another cmc wireing harness to replace one that was underwater. The actuator works fine but I didn't want to run it with bad wire or bad relays. Slowly but surly getting my rig back together. Sure miss going fishing.

 

[Dhadley]

Re: Tach setting for '81 70hp Johnson (poles)

Set the tach on "6".

The motor will idle higher out of the water with no backpressure. Don't set it until you get it in the water. If the idle is about 1000 or so it'll be close depending on how low the motor sits in the water.

Just make sure the carbs are clean and in good working order. If all is as it should be, that motor will live a long time. 5800 is your target wot rpm's with an average load. Champion plugs, fresh 87 octane and good oil as always.

 

[imported_beck]

Re: Tach setting for '81 70hp Johnson (poles)

Thanks for the info.

Another ? When the control was wired with the 48 spl, I could stick a screwdriver or key under the idle lever to test the warning horn. This procedure doesn't seem to work now. I want to check the horn. I could be doing something wrong.

Also after running the motor and I stopped it, I put my hand on the engine block and it was hot almost too hot to touch but when the motor is running I can hold my hand on it.

When I read as a test of the temp. to touch the engine block, this is I suppose while the motor is running?

Thanks again,

Beck

 

[rickdb1boat]

Re: Tach setting for '81 70hp Johnson (poles)

If when the engine is running, you can hold your fingers on the head for a few seconds without burning them, then it is not running too hot. When stopped, it's normal to build up heat. You can also check the warning horn by locating the tan wire going to the temperature sensor on the engine block. Disconnect and ground it with the key in the ON position and the alarm should sound...

 

[imported_beck]

Re: Tach setting for '81 70hp Johnson (poles)

Thanks for the info.

I just wired new cmc ptt harness and operated ptt. It went up then would not come down. Acutator motor open. :'(

Unit bought 07-20-05 from iboats. Used once other that today to check it out.

One step forward two steps back. Oh well.

Beck

 

[mikesea]

Re: Tach setting for '81 70hp Johnson (poles)

Dont know what you mean,actuator motor open.But if the engine wont return down,try switching the relays,if that does it then one of the relays is bad.Check all your connections,its possible one is not making good contact

 

[imported_beck]

Re: Tach setting for '81 70hp Johnson (poles)

What I mean by open is that the windings in the actuator motor are open. I contacted cmc and they aggreaed to replace the motor with a rebuilt one which was ok with me. It is over a year old but only by a few months. They took into consideration that I wasn't used for a year with the hurricane and all. When I dissembled the acutator from the bracked talk about easy to remove. All quality material, stainless, and all. everything came apart with no trouble considering it was submerged. They were very nice to work with.

Beck

Ps: I had tried to operate the motor by itself. Taking the relays out of the circuit. Then I ohmed it out, motor winding open.