84 Evinrude bogging full throttle surge

[Rmillis]

Next time out I will mark the hub just for kicks, and mark the timing marks on the front so it can be seen while underway. I'd like to see if the ignition timing is advancing correctly and or jumping around while problem is occurring and what happens when it runs Like it should. Any other thoughts or suggested greatly appreciated.

( replaced 1 ign coil, plugs, wires, charge coil and trigger coil, power pack. Replaced main jet seal in Carb due to a split seal, adding fuel while inderway doesn't help)

 

[Culpy14]

Compression good(did cranking compression test). Spark doesn't seem to be dropping, used timing light whole underway didn't see a loss of spark or change. Carb is fully open at wot, clear view of what looks like a good fuel spray into the engine.

Also my engine surged like that. It’s the misfire from ignition that is likely the problem, and if it looks like a wide range of ignition problems, I would say it’s your stator.

 

[Rmillis]

Something still needs to produce the voltage. There’s likely a stator somewhere, and magnets inside your flywheel.

What I had one my outboard was an idle problem, but fine while at mid throttle, and reduced power at WOT. It is pretty hard to diagnose without a Peak Voltage Meter, and you’ll end up assuming it’s everything else in the ignition system.

When I used a timing light I would see the misfires happening in all cylinders. By that point I had replaced everything else in the ignition system and tested resistance. My mistake was testing resistance when the engine was hot. That gave me a false reading and kept overlooking the stator.

On my engine it will charge the battery and provide ignition voltage separately. Looks like it’s all in one system for yours.

I could be wrong if the battery is charging, but the symptoms sound as fickle as a stator issue, and very few people will likely mention that on here.

I pulled the flywheel, inspected the magnets, replaced the charge coil and trigger coil. Flywheel aligned to crank for TDC, checked with dial indicator and timing marks. This engine does not have battery charge capability.

Gonna try and get a video next time out aswell..as well...

Thanks!!

 

[Culpy14]

I pulled the flywheel, inspected the magnets, replaced the charge coil and trigger coil. Flywheel aligned to crank for TDC, checked with dial indicator and timing marks. This engine does not have battery charge capability.

Gonna try and get a video next time out aswell..as well...

Thanks!!

Just check the resistance on your stator. Should be 450-600ohms. Do it when the engine is cold, or the resistance reading will be incorrect.

Might help to do it when it’s hot too, since yours happens when it’s under a specific load.

 

[tphoyt]

Used a timing light while underway and problem present, didn't see any change.
Would using a running light be different? If so how would that work..

Yea sorry about that. It was meant to say timing light. You did the right thing.
When you asked about the running light I was so confused then realized I was the one that cause the confusion.

 

[oldboat1]

re. checking for water in the fuel... will be at the bottom of the tank at the pick up. Can you borrow a known working tank?

 

[Rmillis]

Also my engine surged like that. It’s the misfire from ignition that is likely the problem, and if it looks like a wide range of ignition problems, I would say it’s your stator.

By the stator

Just check the resistance on your stator. Should be 450-600ohms. Do it when the engine is cold, or the resistance reading will be incorrect.

Might help to do it when it’s hot too, since yours happens when it’s under a specific load.

I don't have a stator. This only has a charge coil and trigger coil. Both are new and check good. The original charge coil showed signs of leakage and was cracked, even though it was in range of resistance I replaced it anyway. After reading online that the trigger coil would sometimes do intermittent things I replaced it as a "rule out"...

Others mention fuel, I can add fuel while under way and it only boggs more and there's a clear clean spray of fuel in the carb. NO water in tank. It acts like an ignition miss the way it cuts in and out so quickly, but I'll be dammed if I can find it.

I'm not a 2 stroke mechanic but have rebuilt several outboards. I am a automotive mechanic and instructor. I typically don't ask for help, but I'm out of ideas....

 

[saltchuckmatt]

By the stator

I don't have a stator. This only has a charge coil and trigger coil. Both are new and check good. The original charge coil showed signs of leakage and was cracked, even though it was in range of resistance I replaced it anyway. After reading online that the trigger coil would sometimes do intermittent things I replaced it as a "rule out"...

Others mention fuel, I can add fuel while under way and it only boggs more and there's a clear clean spray of fuel in the carb. NO water in tank. It acts like an ignition miss the way it cuts in and out so quickly, but I'll be dammed if I can find it.

I'm not a 2 stroke mechanic but have rebuilt several outboards. I am a automotive mechanic and instructor. I typically don't ask for help, but I'm out of ideas....

Rmillis,

Just a shot in the dark here.

When you worked under the flywheel installing coil and such, did you use the omc alignment tool? Those have to be set just right for flywheel clearance.

 

[saltchuckmatt]

Rmillis,

Just a shot in the dark here.

When you worked under the flywheel installing coil and such, did you use the omc alignment tool? Those have to be set just right for flywheel clearance.

Just re-read all of your posts. You've done everything really...only thing I can think of is you haven't looked at the reed valves, or maybe you have. Frustrating I'm sure.

 

[saltchuckmatt]

By the stator

I don't have a stator. This only has a charge coil and trigger coil. Both are new and check good. The original charge coil showed signs of leakage and was cracked, even though it was in range of resistance I replaced it anyway. After reading online that the trigger coil would sometimes do intermittent things I replaced it as a "rule out"...

Others mention fuel, I can add fuel while under way and it only boggs more and there's a clear clean spray of fuel in the carb. NO water in tank. It acts like an ignition miss the way it cuts in and out so quickly, but I'll be dammed if I can find it.

I'm not a 2 stroke mechanic but have rebuilt several outboards. I am a automotive mechanic and instructor. I typically don't ask for help, but I'm out of ideas....

A little more info, you say 1984 30hp Evinrude (25 cap) is there a model number on the clamp? You say choke plate has been removed. That should have a manual primer system....is it there? Your problem could be there. Here is a description of the alignment ring and the most common things that go wrong when you have a upper end surging issue. 8th spot down in my omc service book.

 

[Rmillis]

A little more info, you say 1984 30hp Evinrude (25 cap) is there a model number on the clamp? You say choke plate has been removed. That should have a manual primer system....is it there? Your problem could be there. Here is a description of the alignment ring and the most common things that go wrong when you have a upper end surging issue. 8th spot down in my omc service book.

Didn't use the omc tool for setting clearance. I did set clearance very carefully. By putting flywheel in place and adjusting both coils one at time until they cleared( barely clear.. but I know it's not the same as a set clearance. )
I will get the model number and take some pics tomorrow. I honestly didn't even think about the manual fuel primer. ..
Maybe it's allowing extra fuel in intermittently..idk.
I will check out images you sent tomorrow.
Long day of setting up my classroom..

I appreciate the help!

 

[saltchuckmatt]

Didn't use the omc tool for setting clearance. I did set clearance very carefully. By putting flywheel in place and adjusting both coils one at time until they cleared( barely clear.. but I know it's not the same as a set clearance. )
I will get the model number and take some pics tomorrow. I honestly didn't even think about the manual fuel primer. ..
Maybe it's allowing extra fuel in intermittently..idk.
I will check out images you sent tomorrow.
Long day of setting up my classroom..

I appreciate the help!

Hope it helps...

 

[Culpy14]

I pulled the flywheel, inspected the magnets, replaced the charge coil and trigger coil. Flywheel aligned to crank for TDC, checked with dial indicator and timing marks. This engine does not have battery charge capability.

Gonna try and get a video next time out aswell..as well...

Thanks!!

Any luck?

 

[saltchuckmatt]

Hope it helps...

More stuff to read....

 

[Rmillis]

Haven't made it back out yet.
However I have removed the fuel pump and pressurized it with the primer bulb, very little fuel came out around the lower screw above the inlet, and possibly from the vacuum port hole. So I ordered a new one. Also, disassembled the carb again and this time I removed the core plugs and ordered a kit. Was pretty clean but I wanted to make sure I wasn't missing something. Also removed the reed plates and checked them out. No cracks or damage, everything tight and lined up. waiting on parts then I'll try again and will post a video if it continues. (84 model evinrude 30hp, block/engine swap from 25/35??painted black, has 1978 25hp carb.) serial plate says E30RCOA.

 

[Rmillis]

More stuff to read....

It does feel like it is sticking. I will disconnect the fuel line from the primer to the carb and plug it next time out as part of the figuring ....