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Troubleshooting / Tune Up 1988 Evinrude E50TSLECC 50 HP

mturner125

New member
I'm struggling to achieve a steady/strong idle on a new to me Evinrude 50 HP. I purchased the boat about a month ago and it was very clear that the prior owner took excellent care of the boat. He was meticulous in the restoration. The motor was purchased new by the prior owner in the late 90s and currently has about 140 hours on it - It got almost no use in the last 5 years (owner reported he started it periodically w/ muffs on).

My first day on the water with it I found that it would not rev past about 3000. I eventually determined that the fuel lines coming off the fuel manifold had perished and were causing debris to collect in the carburetors. I did a thorough clean of the carburetors and ran new lines from the water separator all the way to the carburetors. I also decided to remove the VRO and go with a simple fuel pump and premix. At this point, the boat would idle with the lever fully down (low rpms and not very well) and I'd say I got a 60% success rate in getting the motor into gear without stalling.

I noticed that the rollers (both) within the linkage had fully deteriorated and that some of the linkage measurements were off per the Evinrude Service Manual. This week I replaced the rollers and I attempted to do a link and sync, returning the maximum spark advance to the factory setting and going through the process to set the idle stop screw. I got the motor up to temperature while working on the idle stop. I noticed that the idle adjustment screw required a lot of adjustment to achieve the 800 RPMs required by the process. After getting the motor to approximately 800 RPMs my idle light was showing a reading of approximately 3 degrees before TDC - The manual suggests that the motor should be at 1 degree (+or-1) after TDC.

Question to forum members
- should I back off that idle stop screw which would reduce RPMs and also retard the timing to get it in spec? Any other ideas on how to improve the strength of idle? I've been through the carbs more than once with rebuild kits - they are perfect with the floats adjusted correctly and the fuel is new.

Couple other observations:
  • When doing the link and sync I left the air silencer off because the new gasket I bought last week was falling apart. I noticed that there was some pooling of fuel in the upper carburetor. It didn't appear to be spiting fuel out, just a few drops pooling.
  • Reeds appear to be perfect, I don't see any flaws in them. Frankly, I'm not all that experienced in working on these so I'm not really sure what to look for. I didn't see any pitting, cracks, or any gaps in the reeds.
  • Spark plugs are new as of 2 weeks ago. They're gaped to spec at 030
  • When I measured timing on the number 1 cylinder I noticed that the timing gun did not pick up a signal when connected to the spark plug wire - I needed to move the inductive pickup up near the spark plug to get it to fire.
  • I used a spark plug gap tester - I verified a strong blue spark firing over about a 7/16 gap on both cylinders

Our local Johnson/Evinrude dealer is backed up about 4 weeks right now. I'm on the list and I think I'll have an opportunity to get it in there in the next week. In the meantime, anything else you all would consider doing/testing? I'm considering backing off the idle stop to get back to spec (at/around 1 degree ATDC) and then running a can of seafoam through the engine.
 
Post compression test numbers.----Did you mount the simple pump directly over the pulse port on the side of the top cylinder , yes or no ?----Fact for you.----Maximum spark advance is SET.-----The idle timing is the point where throttle plates OPEN.-----The actual timing when motor idles nicely does NOT matter and looks after itself.
 
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Post compression test numbers.----Did you mount the simple pump directly over the pulse port on the side of the top cylinder , yes or no ?----Fact for you.----Maximum spark advance is SET.-----The idle timing is the point where throttle plates OPEN.-----The actual timing when motor idles nicely does NOT matter and looks after itself.


  1. Will do on the compression test numbers - I probably should have tested that day one.
  2. That's right on the pulse port. I plugged the pulse line that went to the VRO with a stainless bolt and hose clamp. Any known issues with this set up? I'd much prefer to run without the VRO just to reduce the complexity of the system. I'm happy to premix. I used a Sierra Fuel Pump - 18-7352 and connected it to the pulse port on the side of the motor.
  3. The idle speed procedure (Link and Sync - Evinrude Service Manual) suggests that you need to have the boat unrestricted in the water. Bring up to temp. Check idle in forward gear and then adjust the idle speed screw to achieve 800rpms. From what I can tell, and I'm very new to this, is that the idle speed screw influences the position of the pickup under the flywheel. Once you achieve 800 rpms (in my case the idle stop screw was fully/mostly extended - long position) you're to verify idle position in forward gear is 1 degree ATDC plus or minus 1. Good to know on your last point. I was concerned that my reading of approximately 3 degrees BTDC at idle might cause damage to the moto

I really appreciate your help with this.
 
Sorry-----There is no way you will damage motor with idle timing.-------Maximum spark advance is very important and is the one you set !!----Idle timing is the point where throttle plates open.----So that is a CARBURETOR throttle plate adjustment.
 
Sorry-----There is no way you will damage motor with idle timing.-------Maximum spark advance is very important and is the one you set !!----Idle timing is the point where throttle plates open.----So that is a CARBURETOR throttle plate adjustment.


Gotcha. Here is page 1 of the link and sync:
https://imgur.com/a/OsJLhDQ

Just to be clear, I adjusted screw D (idle speed screw) which then moves the spark control rod which is initially fixed at 2.5".
As far as I know, there is no adjustment on the carb to influence idle RPM. The only adjustment available, I believe, is the idle mix screw which should be set initially at 3.5 turns out.
 
Post compression test numbers.----Did you mount the simple pump directly over the pulse port on the side of the top cylinder , yes or no ?----Fact for you.----Maximum spark advance is SET.-----The idle timing is the point where throttle plates OPEN.-----The actual timing when motor idles nicely does NOT matter and looks after itself.

Hey racerone - I finally got an opportunity today to get on the boat. It started up fine and seemed to exhibit the same symptoms - bit of a rough/unsteady idle. I decided to run some fuel through the system w/ seafoam for 15 min on then waiting fifteen minutes before the next cycle. There wasn't a noticeable difference in performance but I'd say that overall it was a bit better than the last time I was out. I used an infrared thermometer on the motor periodically - well after warm up - and I got readings on the cylinder head that was in spec per the manual (between 140-160). I did observe higher temperatures in other places on the block (up to 194.

I did a compression test well after warm up and got a reading on the top cylinder of 130 and bottom cylinder of 136.

Fuel is new, lines are new, fuel pump is new, and I've gone over the carburetors a couple times to make sure they're clean. I used a small strand of copper wire and a plastic wire everywhere I could within the carb in addition to carb cleaner and compressed air. I also verified that the carburetors are moving at the exact same time when they're engaged by the roller/cam. Spark is jumping across a 7/16" gap on both cylinders per my tester.

I'm thinking now, and I could be off base here, that I might pull the intake manifold to inspect the reeds. It seems like a fairly easy process and they very well may be filthy based on the condition I found the carburetors to be in. A new gasket is only 10 bucks and it seems like that would be something easy and relatively inexpensive to check off the list. Any other ideas?
 
I took a 2 cylinder motor apart a while ago where the bottom crankshaft seal was totally worn out.----Did not seal at all.---And could be remove from the housing with one finger.----The high speed jets are sort of hidden inside the very bottom of the float bowls.---Did you confirm they are clean.
 
I took a 2 cylinder motor apart a while ago where the bottom crankshaft seal was totally worn out.----Did not seal at all.---And could be remove from the housing with one finger.----The high speed jets are sort of hidden inside the very bottom of the float bowls.---Did you confirm they are clean.

Good to know on the bottom crank seal. Would the 130+ compression rule that out? On the carbs- yeah, the first time I went through them the high speed orifice was completely blocked up with old fuel line debris. I cleaned both out really well.
 
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