stumped on this

[RLT III]

when i checked coil's they were at or a little over 800 ohms here's the weird thing when i ground to the motor and then checked each coil. #3 registered on the meter where the rest did not

How or why when there's no wires hooked to it

 

[achris]

Re: stumped on this

What is your engine serial number? The reason I'm asking is because in 1981 the 50 Hp was a 4 cylinder. The 3 cylinder 50s didn't start until 1986.

Coils and grounds...
What are you measuring? Primary to ground or secondary? All coils have an internal connection to ground. You also need to have the wires disconnected so you aren't seeing a path through the switch box...

Chris........

 

[Barnacle_Bill]

Re: stumped on this

It's grounded internally and needs to be replaced.

 

[RLT III]

Re: stumped on this

I just wanted to check everything out

#5797770 Chris

I measured secondary to the ground and yes all was unhooked

I'm kinda leaning to what Bhile is saying since the other 2 don't do it

what you think Chris is that one bad ( I have thought that plug was a cleaner then the other 2 but they have spark so

 

[achris]

Re: stumped on this

Hi again,

Just checked out the engine using that serial number, and it definitely has 4 cylinders, ergo, it must have 4 ignition coils...

ok... let's do some ignition coil tests.. (all 4 of them)

I don't know what meter you have. If it's an auto-range meter, set to the ohms position. If it's not auto-range set the meter to x1 ohms position.

With the leads disconnected from the coils, measure across the primary, they are the 2 small terminals. You should see a value of about 0.02 to 0.04 ohms. (that will look like a short...)

Change the meter (if not auto-range) to X100 and measure from the HT tower (top of the coil, it goes to the spark plug) and ground on the engine block (I assume the coils are still mounted to the engine). They should read 9 to 12 (900 ohms to 1200 ohms).

Now check between the coil tower and either of the small terminals... you should get an open circuit... Infinite ohms.

Post the results (include how the meter was configured and which test leads were on which terminals).... and if you have the make and model of your meter I may be able to look it up and know how you should be setting it, or post a photo of it....

Chris..........

 

[RLT III]

Re: stumped on this

I used a multltester model Sp-152a

Chris it's a 3 cyl it matches with a 70 by # add a 0 to 5797770 and you'll find it

So I unhooked it all and followed the book took meter set on RX1 and it read 0.02-0.04 ohms on all 3 by touching test leads between neg & pos terminals

My book says blue colored coils connect to coil tower(where plug wire goes in) and either neg or pos terminal with meter set to RX100 and I got approx 800 -900 ohms on all 3 coils

So it passed test

When I began i did not understand what i was reading so i did it wrong but in that process(for orange colored coils it says connect leads between coil tower and engine ground set on RX100) remember I have BLUE ( and what I did was ground to engine and connected to neg or pos terminal on each coil and #3 coil registered on the meter where as #1 and #2 did not

So with that mistake I think I found a bad coil and here's my theory===
When i checked for spark I got it on all 3 and my issue is with #3 so once the plug is in the block it grounds the coil and the spark never goes through
the plug What do you think

I'll go get plug pics and post

 

[achris]

Re: stumped on this

I used a multltester model Sp-152a

Looks like this....

Chris it's a 3 cyl it matches with a 70 by # add a 0 to 5797770 and you'll find it

I plugged 5797770 into the program and it came up with a 1981 50hp....??? Is this a 'FrankenMerc'???? (even with a 0 at the beginning it shows as a 50....) (Thinks me needs full story here.... Maybe the rest of the engine is 1981 50 and the powerhead is 70?)

So I unhooked it all and followed the book took meter set on RX1 and it read 0.02-0.04 ohms on all 3 by touching test leads between neg & pos terminals

Great!!!

My book says blue colored coils connect to coil tower(where plug wire goes in) and either neg or pos terminal with meter set to RX100 and I got approx 800 -900 ohms on all 3 coils

So it passed test

When I began i did not understand what i was reading so i did it wrong but in that process(for orange colored coils it says connect leads between coil tower and engine ground set on RX100) remember I have BLUE ( and what I did was ground to engine and connected to neg or pos terminal on each coil and #3 coil registered on the meter where as #1 and #2 did not

That would indicate a fault in coils 1 and 2, not 3

So with that mistake I think I found a bad coil and here's my theory===
When i checked for spark I got it on all 3 and my issue is with #3 so once the plug is in the block it grounds the coil and the spark never goes through
the plug What do you think

It's hurting my head!!!

The short lead that runs from the neg terminal on the coil grounds the secondary side of the coil (as required to complete a circuit). That what the second test was checking for...

How are you checking for spark?

I'll go get plug pics and post

ok...

 

[RLT III]

Re: stumped on this

That's the meter all i could borrow here's plug pics
I just held plugs away from metal and looked for spark and was blue on all

my head as well

 

[achris]

Re: stumped on this

Plugs look fine...

Are you using a spark tester to check for spark?

If your getting good spark on all three, why are you looking at the ignition system?

 

[RLT III]

Re: stumped on this

because past 2 times out i lost power at wot the 1 time took fuel pump down and was torn so rebuilt it and the 2nd time have no clue so that's why i performed all the tests and all checks out also i just ran new 30r6 fuel lines mechanic bro in law gave it to me and new bulb, filter, water separator

I've cleaned the plugs twice and they come out like that i kinda thought 3 was clean more so then the others

 

[achris]

Re: stumped on this

...I've cleaned the plugs twice and they come out like that i kinda thought 3 was clean more so then the others

That could indicate water getting into the bottom cylinder, meaning the engine needs 'seals and sideplates' doing. That's the bottom crankshaft seals and the exhaust cover gaskets.... We can deal with that later..

The loss of power sounds more like fuel... Next time out have your deckie give the fuel primer bulb a squeeze (or 2) and see if you suddenly get the power back....

Chris...............

 

[RLT III]

Re: stumped on this

will do Thanks for all the help Chris you do alot