'71 johnson 100hp won't start (new batt, starter, sel)

[JB]

Re: '71 johnson 100hp won't start (new batt, starter, sel)

EEEEK!!!! NO NO NO NO! You might mistake the output terminal of the solenoid for a negative terminal. That would be very very bad news, including destruction of parts, possibly your boat and engine. DO NOT lose focus again. Follow the steps I gave you. If the information you have supplied so far is accurate, and I believe it is, that WILL locate your problem.<br /><br />Hang in there.<br />JB

<br /><br />BTW, all of the measurements I gave you should be made with the starter engaged.

 

[markcv]

Re: '71 johnson 100hp won't start (new batt, starter, sel)

thirdm<br /><br /> We need to go back to turning the motor over with a pull cord. The reason I asked if you could do that is to eliminate any voltage drop while using the starter. If you are going to use the starter than hook some boster cables from your truck to you cranking battery.<br />I am still not sure if you are able to crank this thing easy enough with a rope? A 100hp motor should not crank over so hard with a rope that you cannot start it. Most of the new snowmobles are putting out any wheres from 100hp to 175hp. All are two strokes, and most of them you start with a pull starter. Many are developing this hp with two cylinders. Compressions are up to 150 to 175 psi. So I guss what I am trying to say, are we putting too much load on the starter to even roll this over because of another mechical problem. By the sounds someone has had this baby apart. Let me know if you can pull this over with a rope easy enough that you feel that it could start. If you try the starter,hook the boosters to it to give you some extra waliop.<br /><br />markcv

 

[JB]

Re: '71 johnson 100hp won't start (new batt, starter, sel)

Hey, Mark. Go back and read this history. If what you suggest were true, he would have 10 to 12volts at the starter. He doesn't. He KNOWS that he has a good battery and a good starter. He has prima facea evidence of big voltage drop in the high current circuit.<br /><br />Starting the engine manually would only confirm what he already knows. Why distract him into wasting the time?? Let him get on with finding the bad cable or connection.<br /><br />JB

 

[thirdm]

Re: '71 johnson 100hp won't start (new batt, starter, sel)

i'll get back to y'all after i charge the battery back up (left the key on)!!!!!!!! i'll start w/the voltage test <br /><br />thanks,<br /><br />mason<br /><br />by the way, if anyone wants this tropical depression allison they can have it.....it seems like it is going to be sitting over my house for the next day or so

 

[markcv]

Re: '71 johnson 100hp won't start (new batt, starter, sel)

sorry I was not trying to distract just trying to help. I will stay out of it.<br /><br />markcv

 

[thirdm]

Re: '71 johnson 100hp won't start (new batt, starter, sel)

alright J.B. (or anyone else that can translate this)........<br /><br />i hooked up my voltmeter w/the negative terminal of the battery instead of the engine block ground. here are the numbers<br />....all numbers under load...<br /><br />power to starter: 8 volts<br />power into sel: 8 volts<br />power out of sel: 8 volts<br />top "small wire" of sel": .5 volts<br />bottom "small wire of sel": 8 volts<br /><br />when i use the engine block ground - all of the "8's" become "7's"<br /><br />the battery reads 13 volts alone (as does all other hot connections) and reads 10.5 volts under load<br /><br />..........does this tell me anything????????<br /><br />thanks, <br /><br />mason

 

[Howard Allen]

Re: '71 johnson 100hp won't start (new batt, starter, sel)

It tells me you are either not getting enough current to the starter or the starter is partially shorted internally.<br /><br />To eliminate any line losses (get most current to the motor) Do this: Get a set of battery jumper cables and disconnect the starter motor from the solenoid. Connect one of the black jumper cables to the engine chassis on clean metal (not painted and needs to be shiny). Connect the other end to battery negative. Then connect the red cable to the starter motor terminal nut (not the copper stud) make sure the nut is clean tight and shiny). Connect the voltmeter to the battery properly and then connect the remaining jumper cable to the positive terminal of the battery. If the battery voltage drops below 10.5 volts and the starter motor won't turn the engine then the starter motor is no good - rebuilt or not!<br />You should be able to confirm this by disconnecting the starter motor completely and connecting the OHM meter across the terminal and the case. I bet you will read a very low resistance - in the 2-3 ohm range. Unfortunately I can't tell you what it should read. If the motor does turn it over then you have a wiring problem. This is the procedure I followed to confirm MY starter motor is no good.

 

[JB]

Re: '71 johnson 100hp won't start (new batt, starter, sel)

What Howard suggests will confirm what you have found. When you completely bypass your high current circuit with the jumper cables, she should spin the engine just fine. Because you have 10.5 volts at the positive terminal of the battery, but only 8 is left when you get to the solenoid you have "dropped" too much voltage in the cable from the battery positive terminal to the solenoid. <br /><br />If the connections at both ends are clean and firm and the terminals appear soundly connected, replace that cable. Do not use wire smaller than you take out. Better yet, go to size (4-0). Do not substitute aluminum wire. Expect to pay around $5 per foot for multistrand, tin plated copper wire and get it at a marine house, not an automotive house.<br /><br />If you can see corrosion at one or both terminals you can cut them off, restrip, tin the ends (rosin flux only, no acid) and solder on new, solid copper or tin plated copper terminals. You will need a 100 watt soldering iron or a torch to do the soldering. While you are at this it would be a good idea to renew the terminals on the negative cable, too.<br /><br />You are almost there. <br /><br />Good luck.<br />JB

 

[thirdm]

Re: '71 johnson 100hp won't start (new batt, starter, sel)

thanks howard and J.B.,<br /><br />the only thing i am confused about (please forgive me if i sound stupid - but i am used to auto engines) is the "jump" method. the negative is a no brainer. the positive i am not sure about...do i hook up the cable to the hot side of the selonoid or directly to the starter itself. i know if i hook it up to the selonoid it would just be a "touch" (works on a car!) or do i hook it up to the hot side of the selonoid? if i do that, i can't use the key can i? i am going out of town tommorow - venice, fl - WITHOUT THE BOAT - when i get back i will hopefully be able to fix this thing and get it in the water. i will let y'all know how it turns out. (i'm from georgia, y'all is a perfectly correct term around here!)<br /><br />thanks,<br /><br />mason

 

[JB]

Re: '71 johnson 100hp won't start (new batt, starter, sel)

Do the jump to the hot side of the solenoid. That way you can use the key. I grew up in NC and became a natualized Texan about 30 years ago, so y'all is proper language. I named one of my boats "Heidi Yawl".<br /><br />Good Luck.<br />JB