1972 evinrude 25hp sparkplugs

[nick271]

G'day legends
So I was out on the water today trying to get some fishing in my old outboard was giving me some drama every now and then I'd have throttle wide open but wouldn't get going then after about 30seconds it would take off normaly
Sometime it cut out at half throttle then when trying to restart the motor it was acting like it was flooded and wouldn't restart unless I pulled the fuel line off give it a few pulls with the choke on till it came to life reconnect the fuel line then it would start again
But it was choking and splattering at idle half and full throttle every now and then it would run smoothly for a while then just start up again randomly well under way
I pulled the spark plugs out well I was on the water and they were very wet and oily
Does this sound like a fuel flow error or spark plugs aren't getting hot enough iv uploaded some photos of the plugs they were taken after I got home sorry shoulda taken some on the water

 

[saltchuckmatt]

Sorry and no disrespect.....seems like user error.

 

[racerone]

Some simple testing / inspection needs to be done.-----Post the actual compression test results.----Does spark jump a gap of 5/16" ( 8 mm ) , yes or no ?----Does primer bulb go hard , with no fuel leaking from carburetor?-----Have you cleaned breaker points and inspected bottom of the coils ?

 

[nick271]

Some simple testing / inspection needs to be done.-----Post the actual compression test results.----Does spark jump a gap of 5/16" ( 8 mm ) , yes or no ?----Does primer bulb go hard , with no fuel leaking from carburetor?-----Have you cleaned breaker points and inspected bottom of the coils ?

Compression test showed 122psi top and 121psi bottom cylinder
Primer bulb went rock hard well out on the water today
No fuel leaking from the carbie
I also tried adjusting the air mixture screw well out on the water
Breaker points were cleaned and inspected when I replaced the woodruff key and lapped the fly wheel 3 weeks ago
Motor was running great after that untill today
Havnt checked spark plug gap jump yet but it's where I'm leaning not burning hot enough and causing motor to flood well under way or clogged/dirty carbie sending wrong amount of fuel

 

[nick271]

Compression test showed 122psi top and 121psi bottom cylinder
Primer bulb went rock hard well out on the water today
No fuel leaking from the carbie
I also tried adjusting the air mixture screw well out on the water
Breaker points were cleaned and inspected when I replaced the woodruff key and lapped the fly wheel 3 weeks ago
Motor was running great after that untill today
Havnt checked spark plug gap jump yet but it's where I'm leaning not burning hot enough and causing motor to flood well under way or clogged/dirty carbie sending wrong amount of fuel

Ps spark plugs were replaced 4 months ago but im wondering if there is a replacement for the j4c champion to a hotter plug safely if that would help

 

[tphoyt]

It always hurts just a little when a 72 is considered old
It does sound like possibly a weak spark event.
You’re in good hands with Racer and you will get results.
Best

 

[nick271]

It always hurts just a little when a 72 is considered old
It does sound like possibly a weak spark event.
You’re in good hands with Racer and you will get results.
Best

Yeah but at least a 72 is usaly reliable even when the arthritis plays up it still got me back to the boat ramp

 

[racerone]

Run with a timing light see if you can find which cylinder is missing.

 

[cyclops222]

Too much time doing steady idling. Hotter sparkplug ? What gas to oil ratio are you using ?
You need to call ...NGK sparkplug company... Ask them for a SAFE hotter sparkplug. Another way to reduce the fouling plugs. Is to go to WOT speed for about 2 miles. The heat burns off the oil & black carnon nicely
Or change plugs more often.

 

[Crosbyman]

did the engine always run good or that way in years past .... using the same plug type or did you change anything. ? a dirty carb usually restricts fuel flow. CHeck heat range for plugs maybe try one up the scale.

if the inlet needle was stuck open you would see fuel dripping out all over
but that does not seems to be the case.

how long has it been since you serviced all ignition parts ? it has the old style magneto and easy to check out.

check points condensers, plug wires, coil resistances from plug boots to HV pins look for steady readings if you throttle up and down while checking (while the mag plate rotates).

check oil recirculation line. check/test thermostat

Are you running fresh fuel at 50/1 ...

 

[racerone]

Have the coils been replaced on this motor , yes , no or no idea?

 

[cyclops222]

Almost forgot the best reason for when a motor starts to run terrible !!!!!!!!
Do what I did. Bought the cheapest GALLON of 2 stroke oil !!!!
I fouled up plugs in a hour of less than WOT running. Oil on sparkplugs CAN BE ....Using.... 2 stroke oil .....for AIR COOLED 2 strokes.

The oil in that can is a much higer temperature burning oil !! Most living mechanichs will not figure that out .
I called NGK asked for Technical Support for correct & a SAFE hotter sparkplug for all the trolling time I do with short slow speed moving around. Gave me a SAFE hotter trolling plug AND even a hotter one if I did not go over 1/2 to 3/4 very long. I stick with 1 heat range hotter to do 1/2 hour WOT runs home.

 

[racerone]

Maybe check for thermostat stuck open.----Oil is added to the gasoline to lubricate the internal parts.-----Oil burning off is the unfortunate thing that also occurs.----Smoke does NOT lubricate any parts.-----Why would you use cheap oil in a precision motor ?

 

[saltchuckmatt]

Evinrude/Johnson like champion spark plugs, bar none.

 

[davidmbv]

J6C run better on these than j4c. Stick with Champions and make sure they are gapped to spec. I have a 70,71,72 25hp Johnson and all run J6C. Also clean points every few months if it starts running like crap. Plugs are cheap, if they get fouled, replace.

 

[cyclops222]

I forgot to astate that I bought the AIR COOLED ENGINE oil accidently. Old guys are not always on the ball. My mechanic took the Air Cooled oil. I then bought the Water Cooled oil The plugs cleaned right up with the water cooled engine oil

 

[saltchuckmatt]

Agreed,

Use the 4's and cut back on the 2 stroke oil. Oil is WAY better now, so leaning it back a bit for anyone who calls himself an "old man".

I always clean the plugs. Carb spray, wire brush, compressed air and last but not least, my plumbing torch.

They will last until there's no plug wire.

If anyone doesn't believe it, try it.

 

[flyingscott]

Did you check spark? Have you checked the condensers?

 

[Crosbyman]

Testing caps requires a high voltage leak test.. anything else is subjective . Although shorted or open caps are obvioulsy BAD....

caps tested at low VOM battery levels for resistance and capacitance will not garantee to be good under high voltages....see part#2 below

see magazine articles on the western region AOMCI site by M.Mohat (4 articles)

Magazine Articles | Western Reserve Chapter

 

[flyingscott]

Napa Part # just replace them. SME 185002