Major help needed.. Mercruiser 140 hp 1986

Motodox

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Ok so I've owned this boat for a year and it's been a great boat 1986 Rinker v170. Beautiful boat well taken care of too. Its always been garage stored and winterized and all preventive maintenance done etc.




Here's the deal big weekend I just went through the whole boat checking trim pump fluid and out drive gear oil hitting all grease points etc etc. boat has always ran great with no issues until this big weekend trip of course.



We were out tubing all day Saturday loving life, we start to head back to our camp spot on a cove where we could leave the boat. Soon as we get to idle zone and idle to cove it just dies. Flat out dies no weird noises or anything.



Tried to restart has good cranking power and nothin! Feeling pretty bummed at this point as I had friends down for the weekend and was to be boating Sunday too. So I spend my entire night trying to get this thing running. End up replacing cap rotor wires and plugs for the hell of it. Mr43t plugs which is oem I believe, I also have a electronic ignition with the flame flower coil. I have tons of spark coming from the coil very easy to see but not a bright strong spark from the plugs but there is spark!



Air filter off I pump the throttle and can visually see the carb dumping fuel so I know it's getting fuel. I pulled a plug placed thumb over port and it's getting tons of compression. Going to test compression with gauge when I get home.



Thinking it could be flooding I try starting wot and still nothing. I let it sit over night, still nothing! I'm lost at this point and could realllly really use some help and advice. I mean I have spark, fuel and compression. I don't get it went from running great to not even sounding like it wants to start.



Is it possible to jump timing ? Or maybe get someone could give me advice on how to check that. Also I haven't touched the distributor yet figured it ran great before how would that be my problem. My firing order is 1-3-4-2 starting front to back and on the coil #1 would be closest to the front right of boat or driver seat.



Please guys help me out!
 
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Rick Stephens

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Everything you stated is spot on. Most of the 'instant off' problems are ignition based, not fuel based. Go back through, make sure the interrupt is working properly and sitting in the valley. Make sure you have 12v at the coil + stud. Most electronic ignition do not use resistors from what I have seen.

Even though it doesn't sound like a fuel problem, check your filters.

Others with ideas will likely be better than mine. Right off I don't see anyting any more obvious than the things you are already checking.

Rick
 

Motodox

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Thanks Rick, yes I actually just replaced my filter on the pump and cleaned the screen on the line into carburator before trip.

With key on there should be 12v at the coil or just when starting ?

Also what do you mean by interrupt and sitting in the valley ?

Thank you for the reply and help Rick

Travis
 

Rick Stephens

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With key on there should be 12V at the coil.

The shift interrupt is designed to momentarily ground the ignition when coming out of gear. Purpose bing to unload the drive train so the gears can undog. Here's a page that describes how that works.
http://forums.iboats.com/forum/engin...t-system-works



RIck
 

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Motodox

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Great Info I actually wondered what that switch did, I get it and understand how it works. My question now is how do you know if it's adjusted properly or that it's not grounding my system. ? With it just sitting in nuetral starting position the roller on the switch does sit in the middle so not pushing on either pins. Also my boat has always came out of gear easily. . I'm so worried about not figuring this out
 

Rick Stephens

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You'll figure it out. Some little thing.

The switch is 'open' when the roller is in the valley. Fairly easy to test with an ohmmeter or test light. Switch, when activated, shorts to ground.

Next is probaby hook up a timing light and make sure your spark is in the neighborhood.
 
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Motodox

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Ok thanks a lot Rick, hopefully some other guys on here have some advice as well.

Let me ask you this, if I'm getting spark from my coil and at the spark plugs does that mean my ignition control module in the distributor is good? Is it possible for that to go bad and the coil is firing at the wrong time? Or if it was bad would I just not get any fire?

Also when checking timing I have a timing light, is there a marking and gauge by the crank pulley up front?

Thanks so much for taking the time to help. Really gotta figure this out. Going to do some more work on it today after work.
 

flipbro

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You've got spark you've got fuel. Next thing is do you have good compression? After you verify that the compression is good then start to look at a timming issue.
 

Motodox

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Going to compression test it after work today , but I have to agree with Rick . It went from running great pulling tubers to flat dead no hick ups or sputters just a straight shut down.

Rick could you help me out on those questions in my last post like two post ahead.
 

Rick Stephens

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Rick could you help me out on those questions in my last post like two post ahead.

I don't know what could go wrong with an electronic ignition that would give spark but still not run. However, the easiest way to see if it is doing its job is to hook up a timing light and see what is happening. The damper has a line cut on it. There is a timing indicator on the front cover. Use soapstone or chalk to highlight those and see if you are in the neighborhood. Simple way to make sure the ignition is working when the boat itself won't start.

If I had spark, I would probably use a sniff of starting fluid just to see if the motor will fire - really limit that, starting fluid is too volatile to run it more than a few revolutions. If it won't fire on starting fluid then we probably still have an ignition problem. If it does fire on starting fluid then we probably have a fuel problem.


Rick
 

Motodox

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Thank you Rick you seem really knowledgeable and I appreciate your time helping.
So I got of work I checked the timing got it tdc on compression #1 cylinder and looked at the crank bell the notch was right at 0. Pulled the cap off distributor and the rotor is pointing dead on #1 plug wire. I have spark at the plug.

Tried starting nothin, tried starting fluid nothing. Went ahead and checked all cylinders compression and I'm above 135psi in all cylinders. So I believe compression should be good Correct.

I check the coil with a meter at the + and - with key on and I have 8 volts! Soon as I remove my ground and put to engine block I have 12v. Meaning I'm touching the + on the coil and the neg I'm touching to engine block and I have 12v but soon as I touch to both sides of coil I only have 8v.

Also I have continuity between the + and - on coil. What's this all mean? Bad coil
 

Rick Stephens

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Ground is engine. Other side of coil is tachometer lug.

Trying to figure out what ignition system you have. I'm surprised it doesn't have the DDIS (Digital Distributorless) ignition which has no distributor cap or rotor. If you have standard points then you should probably be replacing points and condenser and setting point gap and dwell as well as timing.
Here's the manual for the standard ignition system:
http://boatinfo.no/lib/mercruiser/manuals/mercruiser10.html#/140

Rick
 

Motodox

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Rick my system has been converted to electronic ignition, has a module under cap with two wires coming out red and black that go to the coil.

You wouldn't be available to talk on the phone for just a brief minute would you. It's hard to describe what I've done through post.

I promise not to take up to much time haha
 

Rick Stephens

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I am happy to help, but have to be tomorrow. I'll PM you my phone number. I am headed out to do confined space rescue training at a mill that closed for maintenance. I am safety officer and one of the medics in the county search and rescue group. We do a lot of technical work on ropes, takes a lot of practice. I'll send you a message later on this evening.

Rick
 

flipbro

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Grab your multiy meter check the resistance. You should get between 0.4 to 2 ohms on pos and neg. Then check from pos to coil wire post should get between 6 to15 ohms.
 

Motodox

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So I just read a sticky on testing the electronics and it says 5-9 volts is what you want at the coil which is what I have, I also have continuity between the post on the coil which I should.

I have check compression I'm over 135psi on all cylinders, I checked the timing tdc on compression #1 cylinder and I'm spot on, rotor button is sitting right at #1 spark plug wire.

I've have spark, I visually see fuel dumping in carb fresh filters good compression. I'm lost!

I've checked all in line fusses and connections, I have a strong battery. Checked the shift interrupt roller is sitting in valley and switch works properly.

Everything works all lights pump, blower and lift.

I have 12v everywhere I should.

IM LOST AND DONT KNOW WHAT TO DO!!

Could I just have to weak of a spark and should replace cap rotor wires ??
 

oldsub86

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check to see if you have power to the coil while you are cranking the engine - if the ignition switch has gone bad you might have power to the coil when the key is on but not when you are in starting position

does the boat have a kill switch on a lanyard? if so, is it ok?
 

biggjimm

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Maybe get a spark gap tester. You said the spark at the plugs was weak? The spark should jump a certain length of gap on the tester. They can be found at any parts store for about $15 or so & will tell you what kind of shape your ignition system is in. Just having "spark" isn't always enough, it needs to be a good strong spark. Good luck & hang in there, you'll get it figured out. Jim.

Hey Rick, if he had a flamethrower coil & an electronic conversion, shouldn't he have 12 full volts to his coil? Aren't those flamethrower's internal resistance? That wouldn't cause it to just shut down, I wouldn't think, but we want his system right & the coil is probably not putting out what it could & should if that's the case.
 
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