1997 2-Cylinder 50hp - One cylinder, then nothing

[webbd]

2 potential issues from my viewpoint:

1. A vacuum line came off of my lower carburetor. After fixing it, I adjusted the idle mixture screws, losing track of the prior settings. I re-indexed by screwing all the way in, then back out 1.5 turns, also tested with 2.5 turns with no luck. What is the correct bench setting?
2. I think the vacuum line issue may have been hiding an issue with my power pack or some other part of my ignition system.

I really would like the boat to be usable for our daughter's visit for Thanksgiving. We're planning to go out on the ocean, but not if I can't get it running reliably.

Story and details below... The story is to add possible details that might help to troubleshoot.

• A couple of weeks ago, I tuned the carbuertors on my J50ESLEUR after replacing the coil. Everything was running swimmingly, but I ran out of gas just as I approached the boat ramp, so was unsure if I had it perfect.
• We were able to take it back out today after it sat for 2 weeks. We started out and I ran it through the range of speeds. All was well. We drove to the north end of the lake (7 miles) and it was there that I started having minor issues. It started idling rough, but stilll ran through the rest of the speed range well.
• We took it to the south end of the lake and up a creek for lunch, and it still idled rough, but I was able to moor to some trees and we enjoyed lunch.
• I started it to head home and it would run on only one cylinder, up to about 3000 RPM, no faster, and again rough idle. I pulled the hood and adjusted the mixture screws to see if I could address a possible over-rich mixture issue without success.
• I looked further to find the vacuum line on the lower carburetor had split where it attached to the top of the carburetor and didn't have a pair of needle-nose pliers available to reconnect it, so we returned to the boat ramp at low speed on one cylinder (about 1 mile).

At home, I started working on it.

1. I trimmed and reconnected the vacuum line, then started the motor. It ran on one cylinder only. (lower cylinder, the one the vacuum line had disconnected from)
2. Playing further with the carburetor mixture screws, I determined that the upper cylinder wasn't firing, not the lower cylinder. I got them totally out of adjustment and didn't pay enough attention to remember how many turns they were from all the way in.
3. I pulled the spark plugs and ran a compression test because I was worried that I'd experienced a mechanical failure. 90PSI on both cylinders - normal.
4. The top spark plug was "mocha" and wet. The bottom one was "dark chocolate" and wet.
5. I started worrying that my new coil might have failed, so I grabbed the old one and attached the primary and secondary from the top plug to the coil (didn't ground the coil). No spark.
6. I tested the charge coil according to the procedure in my book and it tested out at well over 230V.
7. In the process of all this, I pulled the connector spring out of one of the plug wires while trying to remove it from the coil secondary, so made a trip to West Marine and got new plugs and wires (9" wires instead of the original 6" ones because that's what West Marine had in stock)
8. When I got home, I looked up the bench test procedure for my coil. All test numbers were right in the middle of the acceptable range, measured at 76 degrees F. The primary to ground test was right at 0.07 ohms if I remember correctly and the primary to secondary was also right in the middle of the acceptable range (I think 315 ohms on both). The old coil that I replaced a few months ago reads 312 ohms on the top cylinder side primary to secondary and 291 ohms on the bottom cylinder side, with primary to ground of 0.3 on the top and 0.5 on the bottom.
9. I replaced the power pack 8 years ago. I'm looking at buying a new one because it would be less expensive than renting a boat over the Thanksgiving holiday.
10. I haven't tested the power pack because I don't have the peak reading DVOM tool the Seloc book recommends or the Stevens PL-88 load adapter.

I can get a Sierra 18-5785 Power Pack by Thursday or a CDI Electronics 113-5316 by Tuesday. I may also be able to get something from my local Johnson/Evinrude repair shop tomorrow.

Edit - It looks like I can also get a Sierra 18-5768 by Wednesday. I'm trying to determine which is the right replacement part also.

Looking for recommendations while I read up more on troubleshooting.

Thanks,

-DW

 

[racerone]

Sorry there are no " vacuum " lines on that carburetor.-----The wee hose comes from the primer valve.----Puts fuel into the motor for starting when cold.

 

[webbd]

Sorry there are no " vacuum " lines on that carburetor.-----The wee hose comes from the primer valve.----Puts fuel into the motor for starting when cold.

Good to know. Thanks!

If one of those hoses were disconnected and open to air, would it impact idle mixture?

- DW

 

[racerone]

Maybe just a wee bit.----The hole in the nipple is very small and not much air can go through it.

 

[webbd]

Good to know. Thanks!

If one of those hoses were disconnected and open to air, would it impact idle mixture?

- DW

Just checked again after dark to see if I'm getting spark from the top cylinder. I have an old Champion spark tester that lost the screw that takes the place of the spark electrode, but I inserted a lead of monofilament copper to take its place. The spark tester presents a 3/8" gap.

No spark on the top cylinder. I suspect the bottom is the same but haven't tested.

I just replaced the coil, but can buy another. It tests out okay on ohms. I can put the old coil back on. It's shabby and may have a heat soak issue, but it should work for a few minutes.

Reading other threads, I'm seeing 2.5 - 3.5 turns on the low-range mixture screws. I'd like to not have both carburation and ignition issues at the same time.

I'm seeing "Electronic Specialties 640 Dva Adapter" online as a tool to convert a multimeter to a DVOM Peak Voltage reader. It's not expensive. Is this what I need to test the power pack?

 

[webbd]

Looking at discussion and videos on flywheel magnets...

I don't have any reason to think my flywheel magnets suddenly let go, but it could explain some parts of why my engine isn't running well...

The thing is - I tested the pick-up coils and they are measuring enough voltage. Does this mean at least one magnet is in-place?

I'm just trying to narrow down my issue even though I don't have all the right parts to do so.

- DW

 

[webbd]

After consulting with my local Johnson/Evinrude shop, I just ordered a new OMC power pack to replace the West Marine Sierra one that I installed in 2012. The shop owner said that after the test results I provided, the only possible areass of issue are the power pack and the timer base.

I haven't looked at the timer base, but it seems to me that the engine would still get spark if it was out of adjustment, but might not spark at the right time. Probably be a good idea to get a new timer cam roller while I'm at it. The one on there is starting to come apart.

- DW

 

[racerone]

A new powerpack will usually solve this.----If not you will have a good spare.

 

[webbd]

Thanks for the advice @racerone

I should be able to install the new power pack tomorrow evening, provided it doesn't rain. The boat's going in and out of the garage a lot this week.

The shop also told me to index the low-speed mixture screws at 1.5 turns, so I'll start there.

I'm replacing:

1. Power Pack - seems dead to me, or I'll have another spare.
2. Timing roller - I just checked and the clear vinyl on the outside of the installed one took a hike to the bottom of my cowl sometime yesterday. I wonder if this is what caused my initial issue of running on only one cylinder.
3. Fuel enrichment lines - They're 22 years old and the lower one is coming apart.

I'll update the list once it's back together and hopefully running.

- DW

 

[webbd]

It's running, but I'm having issues with timing. I went through the manual, and first thing, I reset the short spark control rod to 2.5" length according to the manual (2 1/2" for models equipped with a 12 amp charging system or 2" for models equipped with a 4 amp charghing system). To accomplish this, I also needed to adjust all the linkages, reset the carburetor WOT setting, etc.

You may be able to see from the picture that the spark control rod wants to be much shorter than 2.5". In this image, it's at its shortest adjustable length of 2.25" between post centers.

Photo of linkage as-of now with throttle closed:


In this image, it's removed, and the engine will idle. If I retard the spark control rod far enough for it to connect with the timing linkage (even at 2.25"), the engine will backfire and stop.

Do I need to get the 2" spark control rod?

Replaced items:

• Power Pack
• Coil
• Throttle roller
• Timing roller
• Female connector attachment for kill switch

Purchased items in addition that I haven't installed yet:

• 2' primer hose

- DW

 

[webbd]

I'll split this to a different thread...

-- DW