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  1. #1
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    Default 1977 Johnson 75HP Bad Pack, Stator, or Timer Base

    Hello all,

    Thanks in advance for any help or advice I may receive for my problem.

    Motor: 75ELR77S
    I have a Seloc manual that covers this motor.

    Compression is as follows:
    130
    125
    120

    Items I have replaced:

    Water pump
    Fuel pump
    fuel lines (from tank to carbs)
    rebuilt carb's...completely including carb kits.
    Installed Tell-Tale on block.
    New oil in lower unit.
    Spark Plugs
    Starter soleniod

    I just purchased this motor to fix and put on my bass boat. I had this motor running before the carb rebuild, but in the water it would die if put in gear. Forward could sometimes be eased up in RPM's before it would die out, but reverse would die immediatly.

    After rebuilding carbs, exact same problem, it would die in gear. Both before and after, it would idle great and RPMs could be increased with the warm up lever. So, I decided to do a decarb just for &^%'s and giggles. Ran a product my boat shop recommended (made by teleflex?) through the carbs, let it sit, and during the run period after letting it soak, after about 5 minutes the RPM's jumped slightly and had a very smooth idle for about 4 seconds then died. Now it has no spark.

    I have eliminated the key switch by disconnecting the appropriate wire from the power pack. I disconnected the rectifier, but still no spark. My manual says I need a neon tester to check the stator and power pack, but I can't seem to find one. I tried taking a few measurements with my multi-meter, but the manual is a little hard to follow. If I did it correctly, my stator resistance is about 6 ohms throughout. I can't seem to get the 150 volt reading that I found on the internet. In fact, I can't find any high voltage readings while cranking.

    My question is this, should I replace the power pack, stator, or timer base first? Money is tight this day and age, and my wife is about to make me live in "that stupid boat"...

    Thanks again for any input.

  2. #2
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    Talking Re: 1977 Johnson 75HP Bad Pack, Stator, or Timer Base

    First, check coils for insulation cracks. Then, check primary and secondary coil winding resistances. If that's ok it could be the power pack or the stator. I have a neon testor, bought it during my racing years 1977-1985, and they weren't cheap. Best to go to a JohnRude dealer who was active in that era and let him test the powerpack. I've had both powerpack and stator fail on a 1975 75. By the way, the compression's low, 150 psi is very good but 130 is not. Motor will run ok but you won't get top acceleration from it. That hurts, because the 75 (as opposed to the 70) was built as a racing motor with port timing built for high RPM. 6500 RPM (with 50% more oil) is moderate for that motor. Use a prop that lets the motor turn at least 6000 RPM.




    Quote Originally Posted by DoubleBarS View Post
    Hello all,

    Thanks in advance for any help or advice I may receive for my problem.

    Motor: 75ELR77S
    I have a Seloc manual that covers this motor.

    Compression is as follows:
    130
    125
    120

    Items I have replaced:

    Water pump
    Fuel pump
    fuel lines (from tank to carbs)
    rebuilt carb's...completely including carb kits.
    Installed Tell-Tale on block.
    New oil in lower unit.
    Spark Plugs
    Starter soleniod

    I just purchased this motor to fix and put on my bass boat. I had this motor running before the carb rebuild, but in the water it would die if put in gear. Forward could sometimes be eased up in RPM's before it would die out, but reverse would die immediatly.

    After rebuilding carbs, exact same problem, it would die in gear. Both before and after, it would idle great and RPMs could be increased with the warm up lever. So, I decided to do a decarb just for &^%'s and giggles. Ran a product my boat shop recommended (made by teleflex?) through the carbs, let it sit, and during the run period after letting it soak, after about 5 minutes the RPM's jumped slightly and had a very smooth idle for about 4 seconds then died. Now it has no spark.

    I have eliminated the key switch by disconnecting the appropriate wire from the power pack. I disconnected the rectifier, but still no spark. My manual says I need a neon tester to check the stator and power pack, but I can't seem to find one. I tried taking a few measurements with my multi-meter, but the manual is a little hard to follow. If I did it correctly, my stator resistance is about 6 ohms throughout. I can't seem to get the 150 volt reading that I found on the internet. In fact, I can't find any high voltage readings while cranking.

    My question is this, should I replace the power pack, stator, or timer base first? Money is tight this day and age, and my wife is about to make me live in "that stupid boat"...

    Thanks again for any input.

  3. #3
    Honorary Moderator Emeritus tashasdaddy's Avatar
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    Default Re: 1977 Johnson 75HP Bad Pack, Stator, or Timer Base

    FLORIDA GATORS
    TEBOW Country



    Please, NO PM's (Private Messages) regarding boat/engine problems. they will not be answered.
    That is what these forums are for. Post your questions, in the appropriate Forum.

  4. #4
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    Default Re: 1977 Johnson 75HP Bad Pack, Stator, or Timer Base

    Quote Originally Posted by tashasdaddy View Post
    Thanks for the link. I found that same page yesterday, but the problem I ran in to is it says check stator resistance from the brown wire to the brown/yellow, but I don't have a brown/yellow wire.

    My wires are as follows:

    to the power pack from the timer base:

    3 white/black
    1 black/white

    to the terminal block from the stator:

    yellow
    yellow/gray
    brown
    brown/orange

    Should I be checking resistance from the brown to brown/orange?

    Thanks,

    Cory

  5. #5
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    Default Re: 1977 Johnson 75HP Bad Pack, Stator, or Timer Base

    Ok, I went back to the drawing board. Using the info found on the link tashasdaddy provided, here is what I have found (swapping Brown/Yellow for Brown/Orange):

    Stator resistance (brown to brown/orange): 672 OHMs
    DVA output from stator (Brown to Brown/Orange): 3.8VAC
    Timer Bases resistance(black/white to all white/black): 8.7 OHMS, 8.7 OHMS, 8.6 OHMS
    DVA output from timer base(same as above): .08 VAC, .08 VAC, .12 VAC (DC was 0,0,.2)
    DVA output from black/white to ground: 1.2VAC (DC was 1.5)
    Disconnect trigger wires retest: .4VAC

    I visually checked the ignition coils, but they appear to be fine. I know that doesn't mean much, but they are not cracked.

    Thanks again.

  6. #6
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    Default Re: 1977 Johnson 75HP Bad Pack, Stator, or Timer Base

    Well, I talked to my boat shop (over an hour away), and told him the situation. He said he would put money on the power pack. I went ahead and ordered it, so we will see if I end up with a $130 dollar paper weight. I'll keep you posted if it fixes the problem.

    By the way Sandhammaren05, what did you mean by 50% more oil. Should I be running a higher gas/oil ratio? I run 50:1, should I run something different for this motor?

  7. #7
    Honorary Moderator Emeritus tashasdaddy's Avatar
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    Default Re: 1977 Johnson 75HP Bad Pack, Stator, or Timer Base

    your compression is fine, you are running 50:1 which is correct.
    FLORIDA GATORS
    TEBOW Country



    Please, NO PM's (Private Messages) regarding boat/engine problems. they will not be answered.
    That is what these forums are for. Post your questions, in the appropriate Forum.

  8. #8
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    Default Re: 1977 Johnson 75HP Bad Pack, Stator, or Timer Base

    I think power paks are like VRO's. Everybody. gets one wether they need it or not. I would like to have all those burned out pak's

  9. #9
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    Default Re: 1977 Johnson 75HP Bad Pack, Stator, or Timer Base

    6000-6500 RPM 50% more oil.
    over 6500 RPM double oil.
    alternative: use E-tec XD-100 oil at 50:1 at
    any RPM. Powerpacks are cheaper on Ebay if
    you can find one for your model ... .



    Quote Originally Posted by DoubleBarS View Post
    Well, I talked to my boat shop (over an hour away), and told him the situation. He said he would put money on the power pack. I went ahead and ordered it, so we will see if I end up with a $130 dollar paper weight. I'll keep you posted if it fixes the problem.

    By the way Sandhammaren05, what did you mean by 50% more oil. Should I be running a higher gas/oil ratio? I run 50:1, should I run something different for this motor?

  10. #10
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    Exclamation Re: 1977 Johnson 75HP Bad Pack, Stator, or Timer Base

    Wrong. No one knows 75s better than I do, including the mfr. (now defunct).


    Quote Originally Posted by tashasdaddy View Post
    your compression is fine, you are running 50:1 which is correct.

  11. #11
    Moderator JB's Avatar
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    Default Re: 1977 Johnson 75HP Bad Pack, Stator, or Timer Base

    Quote Originally Posted by tashasdaddy View Post
    your compression is fine, you are running 50:1 which is correct.
    Exactly.

    The 75 was not designed to be a racing motor, though it made a good one correctly modified. The problem is that if you treat it like a racing motor it will be temperemental as all get out.

    Your SELOC manual probably has you misguided on the link 'n' synch. Get an OEM Manual.

    On your ignition problem. What do you suppose the odds are that three coils that were working fine a minute ago ALL fail at once? There is room for some logical thinking here.

    Sandy probably know a lot about the 75 as a racing outboard. That does not make him more expert than the guys who designed it. He surely is no expert in dealing courteously with other JohnnyRude experts.

  12. #12
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    Exclamation Re: 1977 Johnson 75HP Bad Pack, Stator, or Timer Base

    Wrong again. The 70 was designed for normal use, the 75 powerhead was designed only as racing motor, the port timing is completely different than on the 70, and the standard compression is 140-155 psi insterad of 120-130 psi (the 70 has a thicker head). No modification whatsoever was necessary for racing (the shortshaft is the racing model, and the longshaft powerhead is exactly the same), and in both APBA and NOA no modification was permitted. the motor turned 6000-7000 RPM on pad-V-bottoms, and 7000-8000 RPM on tunnels. Double oil over 6500 RPM or pay the price.



    Quote Originally Posted by JB View Post
    Exactly.

    The 75 was not designed to be a racing motor, though it made a good one correctly modified. The problem is that if you treat it like a racing motor it will be temperemental as all get out.

    Your SELOC manual probably has you misguided on the link 'n' synch. Get an OEM Manual.

    On your ignition problem. What do you suppose the odds are that three coils that were working fine a minute ago ALL fail at once? There is room for some logical thinking here.

    Sandy probably know a lot about the 75 as a racing outboard. That does not make him more expert than the guys who designed it. He surely is no expert in dealing courteously with other JohnnyRude experts.

  13. #13
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    Default Re: 1977 Johnson 75HP Bad Pack, Stator, or Timer Base

    Easy folks, I didn't mean to start a fight. I was just looking for some input on my problem. Like everyone here, I don't want to spend money on parts that I don't need, so that's why I came to you folks.

    Whether it is a racing motor or not, it is not setting any speed records while it is sitting in my shop, and if I ever get it running, it won't be used for racing in my situation. It's just going on a 16' tri-hull bass boat to go to and from fishing holes. What ever is decided in the end, I will run the required oil to gas ratio. You fine folks know more about this stuff than I do. I'm just looking for help on getting my combination racing/non-racing motor running...

    Thanks again.

  14. #14
    Moderator JB's Avatar
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    Default Re: 1977 Johnson 75HP Bad Pack, Stator, or Timer Base

    Just feed her 50:1 and don't exceed about 6,000rpm, DBS, and you will be fine.

    You probably need either a stator or a powerpak. Sorry I can't tell you which.

    Perhaps someone will come along with good advice and no colossal ego to protect.

  15. #15
    Vice Admiral jay_merrill's Avatar
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    Default Re: 1977 Johnson 75HP Bad Pack, Stator, or Timer Base

    My two cents on the matter is as follows:

    First, the 75hp triples was not the only OMC triples to have compression values in the 140 - 150 range. My 1972 Johnson 65hp motor had values in the high 140s when I bought it a little over three years ago, and it still shows values in the 130s, even though I have run it for hundreds of hours since then. It also runs very nicely the way it is, TYVM.

    The only thing that concerns me about your motor, is that the difference between the low number and the high number, is approaching the 10% differential that most people don't like to see. For the cost and time involved, I might be tempted to slap a new head gasket in the motor, just to see what happens. A manual decarb of the head and pistons might not be a bad idea, while your "in there." None of this is to say, however, that your motor will not be perfectly usable for some time to come.

    I would be less inclined to think in terms of a timer base for an "instant" ignition failure on all three cylinders, than I would of either a powerpack or a stator. I also would not be looking at the ignition coils as a starting point, simply because it would be extremely rare for all three of them to "roll over and die" at exactly the same time. As JB said, the odds of this just don't favor the supposition that this is the problem.

    On the other hand, this scenario is quite common in regard to powerpacks and can happen with a stator. Since, in my experience, the powerpacks seem to be more "finiky" than stators, I'll stick my neck out and say that my guess is that this is where your problem lies. Even if it is not, it has also been my experience that motors this old, tend to need a complete ignition system rebuild for maximum reliability, so it isn't the end of the world if the stator turns out to be the culprit.

    As far as internet sources of info for "ohming out" ignition components, go with the OEM service manual for your year and model. If I had a buck for every time I have seen incorrect info published on the internet or in generic manuals for these motors, I could buy you a new powerpack as a gift.

    BTW, Sierra and CDI make ignition parts for these motors. Since the parts that OMC/BRP is selling these days for motors of this vintage are aftermarket items anyway, you may as well save a few bucks by going directly to aftermarket sources.

    Let us know how you make out.

  16. #16
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    Default Re: 1977 Johnson 75HP Bad Pack, Stator, or Timer Base

    Hey Guys,

    I'm curious if anyone has an answer for this. I was trying to get prepared to replace other parts if my new power pack doesn't work, and while looking on Iboats' web site for other ignition parts, they don't have anything for my 75HP. They have the 70HP listed in my year model, and compared to another web site on power packs, they use the same part number. Does my motor take the same ignition parts as the 70HP?

    Thanks

  17. #17
    Vice Admiral jay_merrill's Avatar
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    Default Re: 1977 Johnson 75HP Bad Pack, Stator, or Timer Base

    Go to www.shop.evinrude.com and find your motor in the "Parts" section. You'll have to work your way through the various links to get to the ignition parts section for a 1977 Evinrude 75hp motor. When you get the site figured out, leave that page open and then open another for whatever motor you are trying to compare parts on. You should be able to track the parts, one at a time, for matches on part numbers.

  18. #18
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    Default Re: 1977 Johnson 75HP Bad Pack, Stator, or Timer Base

    I got my new power pack in, and the beast is alive again. She is a little sluggish getting to WOT, but I haven't done the link and sync yet. It doesn't help by choking while it is bogging, so I think it might be timing. It doesn't immediatly die going into either gear now, so we will see.

    I have another question about this motor though: I'm not sure what it is called, so I'll try and describe it as best I can. The upper part of the lower unit that connects to the lower part of the ?pivot arm? where the shift rod protrudes through; I am getting water gushing out of the spot where the shift rod is. Is this normal? I also have water coming out of a little hole on the front of the lower unit towards the transom above the cavitation plate. Is this normal as well?

    My 35 HP johnny doesn't do this. I am getting a constant stream of water out of the tell-tale that I added.

  19. #19
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    Default Re: 1977 Johnson 75HP Bad Pack, Stator, or Timer Base

    Quote Originally Posted by jay_merrill View Post
    Go to www.shop.evinrude.com and find your motor in the "Parts" section. You'll have to work your way through the various links to get to the ignition parts section for a 1977 Evinrude 75hp motor. When you get the site figured out, leave that page open and then open another for whatever motor you are trying to compare parts on. You should be able to track the parts, one at a time, for matches on part numbers.
    Thanks Jay. I cross referenced a few parts (i.e. stator, coils, timer base), and the Iboats parts for the 70 HP matches the other sites 75 HP, and since Iboats is cheaper, I'll be using them from now on.

    (all this was before the loss of spark):Can a bad rectifier cause a power pack to go out, or will it just make it ground out? I removed my rectifier, and the red wire was very corroded, so I soldered a new wire close to the base and wrapped in heat shrink tubing. I plan on replacing this very soon, but I'm worried if it is failing, it might burn up my new power pack.

    Thanks again.

  20. #20
    Vice Admiral jay_merrill's Avatar
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    Default Re: 1977 Johnson 75HP Bad Pack, Stator, or Timer Base

    Sounds like you are talking about the bottom of the exhaust housing, where it meets the bottom of the swivel bracket. My motor has hydro-electric shift, so I'm not familiar with how the shift rod is sealed, but there probably is one involved.

    The stream of water from the area above the cavitation plate is normal - its a drain hole.

  21. #21
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    Default Re: 1977 Johnson 75HP Bad Pack, Stator, or Timer Base

    i do not own your exact motor but i have worked on a few , i can say thay that i own a 76 model johnson 85 abd they will go threw a power pack every 2-3 years ( just the nature of the motor ). maybe that is something to keep in mind with yours.

  22. #22
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    Default Re: 1977 Johnson 75HP Bad Pack, Stator, or Timer Base

    Every 2-3 years...huh. That sucks. Is it possible in your case there is another component not up to par that is frying power packs? It just seems silly that an expensive component like this would go out that often.

    I think I'm going to go ahead and replace my coils and rectifier just to make sure I don't have a failing component that fried the original pack.

  23. #23
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    Default Re: 1977 Johnson 75HP Bad Pack, Stator, or Timer Base

    Some say that a weak stator is the primary cause of premature powerpack failures. I can't say that I know that for a fact, but perhaps some of the former OMC mechs here will offer an opinion.

  24. #24
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    Default Re: 1977 Johnson 75HP Bad Pack, Stator, or Timer Base

    Quote Originally Posted by DoubleBarS View Post
    Can a bad rectifier cause a power pack to go out, or will it just make it ground out?
    The rectifier converts the 300VAC that the stator produces to DC voltage for the charge system, while the powerpack recieves its power directly from the stator, so I wouldn't think the rectifier would be the cause of a failed powerpack. See my other post about a weak stator.

  25. #25
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    Default Re: 1977 Johnson 75HP Bad Pack, Stator, or Timer Base

    Hey Guys,

    I got the new rectifier on, but my boat mechanic suggested I wait on the coils until they actually go out. I got some other advice from him, but wanted to get some second opinions.

    When I rebuilt the carbs, I noticed that the bottom carb was the only one that had a silver plug in, what I assume is, the low speed passage way. There are two holes either side of the float, and the plug was on the side with the throttle arm. The middle and top carbs had no plugs on the inside. My mechanic said that all carbs need the plugs, so I pulled the carbs and installed them, but haven't run it yet. What do ya'll think?
    Did the guy before me rebuild the carbs wrong?

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