evinrude e150stlcos

[1983 ercoa 21']

This motor is on a tri toon I built.
It has a 15 pitch 4 blade and as always ran 5000- 5400 rpm took out one day after idling around it ran up to 5200 and slowly dropped to 3000 rpm so I pulled it to a idle took off same thing. Then it started running fine.
Next time out ran good for awhile then back to 3000 rpm .
Here's what has been tested.
Compression is 100 psi with the exception of one which is 92 well within the 10% allowance.
Spark jumps 3/8 inch.
I had a new stator and timer base I'd been meaning to put on due to some wires on timer base and gouges in the stator from previous owner magnets coming lose. Still 3000 rpm came home put in new plugs ,kitted fuel pumps yes switched to the older v6 duel pumps. checked carbs. Back to the lake improvement 4200 rpm riding around ran out of fuel switch over to back up tank . And noticed the quick connect was leaking just happened to have one with me replace it hoping I had found my gremlin but guess not still 4200. Any ides or thoughts?

 

[emdsapmgr]

Check to see if you have spark on all 6 plugwires. Either the cyl-drop test, or check spark with a timing light. Make sure you check only after the engine is fully warmed up. Ignition problems may not show up when the engine is cold (recently started.) Make sure none of the plug wires are arcing to ground.

 

[jakedaawg]

I agree with the above. You will probably find a xylinder dropping @4200 and two @3000.

Figuring out why will be.more difficult. Its unlikely two coils go bad at the same time. But check and clean all the grounds for the coils and amphenol connectors for the pack/packs.

 

[1983 ercoa 21']

Check to see if you have spark on all 6 plugwires. Either the cyl-drop test, or check spark with a timing light. Make sure you check only after the engine is fully warmed up. Ignition problems may not show up when the engine is cold (recently started.) Make sure none of the plug wires are arcing to ground.

I failed to mention the spark test with timing light has been done. The spark issue was my 1st search thinking I had a power pak going bad.
It also has new plug wires that are a year old

 

[1983 ercoa 21']

I agree with the above. You will probably find a xylinder dropping @4200 and two @3000.

Figuring out why will be.more difficult. Its unlikely two coils go bad at the same time. But check and clean all the grounds for the coils and amphenol connectors for the pack/packs.

Grounds is the one thing I haven't checked . I'll do so tonight.
Question a power pak could they just be causing it to drop one cylinder at a time ? I always thought they were good or bad meaning all cylinders per pak wouldn't fire

 

[1983 ercoa 21']

I was lucky enough a year or so ago to purchase all the new ignition parts from someone that was unfortunate by not doing a compression test . I was looking at the coils in the box the other day and everyone of them was studio the box . Guess they will be no good now since they are leaking.

 

[jakedaawg]

Yes, power packs can do weird things. Its best to test every thing else before purchasing though. No one likes $200 paperweights.

You have yet to confirm its spark yet also, hencd the spark tests.

Cdi .com has a good troubleshooting guide if you don't have the manual

 

[1983 ercoa 21']

Is it possible that a rectifier could cause any of the issues I'm having? Tach is nice and smooth

 

[1983 ercoa 21']

According to the cdi Web site says the power pak should ohm between 100-200 and if there is a 10% difference between the 3 sensor wires it should be replaced.
New pp Installed last season
142.3
170.0
158.2
Which is over 10%

Older pp
91.7
87.1
95.4

I really feel the older pak is on its way out and is my problem but what about the newer on that is in the mid 100s but has 10% difference

 

[1983 ercoa 21']

All readings were double checked with a second meter

 

[1983 ercoa 21']

Still looking for some input

 

[1983 ercoa 21']

Guess you are as stumped as I am . But hopefully I figured something out ! I'll let you know

 

[1983 ercoa 21']

Don't always trust a ohm test on a timer base .
In my case here using 3 different meters to make sure ! Tonight I broke out the dva adapter and done a voltage test voltage should be between 0.6 and 2.5 cranking. The voltage was low on that side causing my problem. Changed timer base with one I had on a spare motor and I have good fire on all 6 now thanks to all that helped

 

[emdsapmgr]

I'm a fan of using the cranking voltage as an ignition component condemning criteria. (stator and timer base) Glad yours worked out!

 

[1983 ercoa 21']

I'm a fan of using the cranking voltage as an ignition component condemning criteria. (stator and timer base) Glad yours worked out!

I definitely learned a lesson.