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engine timing question

K

kbcave

Contributing Member
1987 evinrude 70hp ELCOS, do these engines have a timing advance system ? If so how does it work and can it fail, working sometimes and not sometimes.. Bottom cylinder has 105 compression, has fuel and spark to the cylinder but makes no difference in the running of the engine when the plug wire is on or off,,,i have replaced every ignition part except the stator and it does test good on the multi meter..Thanks again Kevin
 
You say that the bottom cylinder has compression, fuel, and spark... you are mistaken about one of those areas, otherwise it would certainly fire.

Spark plugs should be Champion QL77JC4 plugs gaped at either .030 (long life) or .040 (super strong spark)

The timing is set by the flywheel key keeping the flywheel and the crankshaft aligned. Unless that key is sheared (usually due to not being torqued to 105 foot pounds), the engine is in time. Even if the key was just halfway sheared, the engine would not run at all.

Having the proper spark can only be determined if the test id using the recommended procedure of having the spark jump a 7/16" "Air Gap". The spark must jump that 7/16" air gap with a strong blue lightning like flame... a real SNAP! Does it?
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(Spark Tester - Home Made)
(J. Reeves)

You can use a medium size philips screwdriver (#2 I believe) inserted into the spark plug boot spring connector, then hold the screwdriver shank approximately 7/16" away from the block to check the spark or build the following:

A spark tester can be made with a piece of 1x4 or 1x6, drive a few finishing nails through it, then bend the pointed ends at a right angle. You can then adjust the gap by simply twisting the nail(s). Solder a spark plug wire to one which you can connect to the spark plug boots, and a ground wire of some kind to the other to connect to the powerhead somewhere. Use small alligator clips on the other end of the wires to connect to ground and to the spark plug connector that exists inside of the rubber plug boot.

Using the above, one could easily build a spark tester whereas they could connect 2, 4, 6, or 8 cylinders all at one time. The ground nail being straight up, the others being bent, aimed at the ground nail. A typical 4 cylinder tester follows:

..........X1..........X2

.................X..(grd)

..........X3..........X4

This can obviously be modified to a 6 or 8 cylinder setup tester.
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Perhaps spark is getting to the cylinder but not in proper time? Did you replace the trigger/timer? Guess you did, but just double checking. Did you check the stator using proper procedure as for example found in the free on line diagnostics manual which is provided by CDI Electronics?
 
I tested the spark with a screwdriver, it will jump 7/16' the spark narrows up the further the gap. it is a strong blue spark you can hear it zap. any further away it turns yellow towards the center of the gap. I started the engine up with the bottom plug out and it blew gas onto my hand.
 
I replaced the timing base assembly. I checked the stator how it is done on you tube..i will find the cdi method..
 
could you elaborate on the sleeve cylinder position, thanks two times ago I had the boat out ran all day on three cylinders except for idle. before that day I had it out and had to idle back to the boat launch on two cylinders.
 
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Facts for you.------ELCOS is NOT a 1987 model !!-----And 105 PSI in not near enuff compression.-----Check the fuel pump diaphragm , it may be ruptured.-----Disregard the sleeve position as that does not apply to your model !!
 
sorry my mistake its an 85, boat is an 87..i have been through the fuel pump diaphram and it is good why would the miss sometimes clear up and motor run fine, sometimes all day?
 
flyingscott said:
Is the bottom plug clean?
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yes the bottom plug comes out white but wet with gas, while the other two plugs look like they've been firing..they are new. of course ive swapped the plugs around but remains the same, ive replaced plugs, coils, power pack timing base..been through fuel system..
 
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I may have overlooked it but I don't see any mention of whether the VRO is still in use or if you switched to a small regular fuel pump. Anyhow, if there is a fuel pump pressure hose going to a #3 crankcase fitting... check that hose to see if fuel may somehow be draining from the pump. Yes, I know you said that you checked the pump diaphragm, (humor me).

Switch the bottom carburetor with the top one to see if the problem follows the carburetor. If it does, then obviously there is a carburetor problem.
 
The VRO pressure hose would be leading to the crankcase (cylinder #?... Not sure of the number). When the piston is on its downward stroke, that crankcase pressure would cause the VRO diaphragm plunger to operate. BY the same token, If somehow that VRO has fuel leaking past the diaphragm, it would be finding its way down that hose and into the cylinder. A remote thought but worth getting out of the way if nothing else.
 
thank you..swapping carbs now. i appreciate your help. without it i would have no where else to turn to. except boat shop
 
joereeves said:
The VRO pressure hose would be leading to the crankcase (cylinder #?... Not sure of the number). When the piston is on its downward stroke, that crankcase pressure would cause the VRO diaphragm plunger to operate. BY the same token, If somehow that VRO has fuel leaking past the diaphragm, it would be finding its way down that hose and into the cylinder. A remote thought but worth getting out of the way if nothing else.
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it appears the bottomcarb was flooding. Ordering kits for them now..
 
You know you're a lot of help. Looks like a pretty rude post. If we don't have the knowledge that you do we aren't worthy. Fact for you. You're an idiot!!
 
kbcave said:
You know you're a lot of help. Looks like a pretty rude post. If we don't have the knowledge that you do we aren't worthy. Fact for you. You're an idiot!!
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KB.... Whenever slamming someone, for any reason, make absolutely sure that you've included type that identifies whoever rubbed you the wrong way. As it stands, the above quote could be aimed at a few individuals, including myself which I believe is unwarranted and not taken lightly.
 
KB, what prompted that remark? Seems folks today are overstressed, sorry if anyone offended you. We are all in this world together. Have to overlook others faults. Nobody is perfect except the guy they butchered on the stake 2000 years back. Certainly some of us here can be old and a bit grumpy. As Bobby Dylan made that ever famous quote......"the times they are a changin' ".........2 mass shootings in 2 days......WTF?
 
joereeves said:
KB.... Whenever slamming someone, for any reason, make absolutely sure that you've included type that identifies whoever rubbed you the wrong way. As it stands, the above quote could be aimed at a few individuals, including myself which I believe is unwarranted and not taken lightly.
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sorry, that was for racerone. this is not the first time. id rather have no help than being slammed for accidently put up the wrong year and being talked to like I was an idiot.
 
timguy said:
KB, what prompted that remark? Seems folks today are overstressed, sorry if anyone offended you. We are all in this world together. Have to overlook others faults. Nobody is perfect except the guy they butchered on the stake 2000 years back. Certainly some of us here can be old and a bit grumpy. As Bobby Dylan made that ever famous quote......"the times they are a changin' ".........2 mass shootings in 2 days......WTF?
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(Facts for you.------ELCOS is NOT a 1987 model !!-----And 105 PSI in not near enuff compression.-----Check the fuel pump diaphragm , it may be ruptured.-----Disregard the sleeve position as that does not apply to your model !! )

Above was from Racerone. if you were actually trying to help some one would you at least tell them, what model year it is. no, he was slamming me for not being as knowledgeable as him..
​
 
If you post the wrong year you might get the wrong information in reply.----An 85 model is a 49 cbic inch motor.----An 87 model is a 56 cubic inch model with a much different block !!----And I have no idea of what you know or what you do not know about your motor.------105 PSI compression is not near enuff for that motor to run properly.-----Sorry if you can not accept that fact !!
 
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Racer has low tolerance for error. He is our senior tech and we know him and treasure him. At times he may insult people but maybe he learned it from his Dad, or other peers along the way. Even Jesus insulted/repremanded his apostles at times, when their intentions were good, but they made mistakes. Your mistake on year was nothing, but your snap at Racer drew blood. I know your a good person. Mistakes are human.
 
Ha! Joe your our senior tech too. I don't ever want to make this forum social, but we need to keep it running smoothly, not like a 175 with only 3 rebuilt carbs.
 
racerone said:
If you post the wrong year you might get the wrong information in reply.----An 85 model is a 49 cbic inch motor.----An 87 model is a 56 cubic inch model with a much different block !!----And I have no idea of what you know or what you do not know about your motor.------105 PSI compression is not near enuff for that motor to run properly.-----Sorry if you can not accept that fact !!
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I tested the compression again and used a wrench to tighten it. they all read 125
 
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