solenoid test for 72 evinrude 100ho

[dstom]

I think my starting problems are in the solenoid, but I want to make sure it is the solenoid first. A friend suggested that I connect the positive lead of a multimeter to the power in post and the negative lead to the power out post. When I do that, what readings should I expect (with key on and in start)? Are there any secondary tests I should do to confirm the solenoid is bad? If the solenoid is good, I will be testing and probably replacing wires to the remote control. Is that the correct procedure?

Thanks for all your help and guidance!

ps- the starter turns the motor but very very slow. That is not the case when the positive battery wire is connected straight to the starter.

 

[emdsapmgr]

Re: solenoid test for 72 evinrude 100ho

I'd hook a set of jumper cables from a good battery direct to the starter. If it turns over at normal cranking speed, the starter should be ok. If the starter turns over slowly, you could have some bad brushes at the commutator. These are replaceable. You've done the correct test and sounds like your starter is OK. Solenoids can go bad with age. They can get arcing/carbon buildup on the contact faces and may not pass current properly-making you think it is a starter issue. I'd consider replacing the solenoid. It is unusual to replace wires to the control box-unless they have deteriorated and the insualtion is coming off.

 

[F_R]

Re: solenoid test for 72 evinrude 100ho

I think my starting problems are in the solenoid, but I want to make sure it is the solenoid first. A friend suggested that I connect the positive lead of a multimeter to the power in post and the negative lead to the power out post. When I do that, what readings should I expect (with key on and in start)? Are there any secondary tests I should do to confirm the solenoid is bad? If the solenoid is good, I will be testing and probably replacing wires to the remote control. Is that the correct procedure?

Thanks for all your help and guidance!

ps- the starter turns the motor but very very slow. That is not the case when the positive battery wire is connected straight to the starter.

Actually there are two tests for a solenoid. The first one is for the pull-in coil. But since yours is activating and trying to power the starter, no need to do that one. The wires to the control and stuff are also ok, or it wouldn't activate.

OK, second test is a voltage drop test across the main contacts. It is done exactly as you describe, with a multimeter. A perfect solenoid would register zero when cranking, battery voltage when not cranking. Since it is probably not perfect, it may not get clear down to zero, but should be low.

Other tests that should be done are a similar voltage drop test across the battery cables (both of them). Red lead of multimeter always goes to the end closest to the + battery post. Black lead to the other end. There will always be some voltage drop across a battery cable, but it should be low. Note that it will be higher if the starter is dragging or stalled. You just gotta use common sense in interpreting the results. I won't take the time here to explain Ohm's Law, which relates voltage, amperage, and resistance. But understanding that relationship explains why the voltage drops vary.