Experts Needed - 55hp stalls at idle when warm.

[imported_Archer]

Evinrude
55975c
C7043832
55hp
1979

Problem: The motor idles fine when cold and I am able to cruise the lake without issue until warm. The motor always runs great once out of idle. At high speed it runs beautifully until I drop the rpm and come towards idle, it then dies slowly or just quits. If I hit the choke, it fires back up until it seems to starve itself again. When the motor is warm, it will die and is very difficult to start and get into gear again to get off of the lake. I would have to jam it into gear and hope that it gets over the ?stall ?hump? and doesn?t bog out and die. (don't want to trash the motor) I can adjust the idle, but it seems to not be very responsive and is maxed out in adjustment. It will also intermittently idle fast and idle slow without being adjusted. I am using an OEM manual for all settings.

What I have done so far to the motor:
1) Complete bore, new pistons, rings, ; compression, leak-down and all appear good, within recommendations etc...
2) Carb rebuilds, link and sync, idle jets, new floats; all appears to be okay, I was very thorough.
3) New bulb, line, gas tank
4) New plugs, gap, coil inspect; spark is great and the coils are newer and show no cracks etc..

Any direction guys? Timing adjustment, fuel pump diaphram, stator? I'm just about to retire from boating at the age of 36!!!!


Archer

 

[tashasdaddy]

Re: Experts Needed - 55hp stalls at idle when warm.

there was a update on the chokes on those motors years ago, it is a heat sensor choke, that operates till the motor gets warm, then cuts out. could be as simple as readjusting you idle went the motor is warm. i am not sure of what to change. but will research.

 

[imported_Archer]

Re: Experts Needed - 55hp stalls at idle when warm.

tashasdaddy,

Thank you for your insight, I am really at a loss of how to make this motor work properly. The motor is very cold blooded, which may be an indication?!? If you can find out anything regarding the choke mod., please let me know. When I try to adjust my idle when warm, it doesn't do much of anything. I was told that advancing the pickup timing for the carbs from 3% to 4% might make a difference. What are your feelings about this? ANd how do I do that, with a timing gun?

Archer

 

[F_R]

Re: Experts Needed - 55hp stalls at idle when warm.

I don't know if the choke modification will help you or not, but what it does is eliminate the automatic partial choke during warm-up feature, instead giving you total control of the choke via the choke switch. It is worthwhile to do the mod and won't hurt anything. To do the mod, at the terminal strip locate the purple with yellow stripe wire going to the choke solenoid. Remove that wire (only) from the terminal strip and move it to the screw terminal with the two purple with white stripe wires. That will make two purple/white and one purple/yellow wires under that screw. Leave the other purple/yellow where it is--it won't be doing anything anymore.

I wonder about your statement about adjusting the carburetor. What are you adjusting? There is no adjustment, everything is fixed jets. There are 3 jets (orfices) in each carb, and the upper carb takes different ones than the lower. Could you have them mixed up? Are you positive that they are clean?

 

[tashasdaddy]

Re: Experts Needed - 55hp stalls at idle when warm.

i PM'd F_R to help on this as he has more experience with that.

 

[imported_Archer]

Re: Experts Needed - 55hp stalls at idle when warm.

Your correct about the carbs, they are fixed jets. I triple checked them and the correct orifice sizes are in the correct ports. No, they are not clogged. Removed, cleaned, wired, and soaked them.

I will try the choke mod., even though I don't fully understand the concept. I didn't know it had an "automatic partial choke during warm-up feature." With my limited knowledge, I thought that it was either on or off.

Again, I really appreciate all of your Expert advice. Please keep the ideas coming so that if this doesn't work I'll have something else to chase.

 

[tashasdaddy]

Re: Experts Needed - 55hp stalls at idle when warm.

do the choke. that way, it is not adding fuel to air/fuel mix, without you choking it. by adding fuel, it is effecting your cold idle, and thus you warm idle. it may be as simple as readjusting the idle speed stop screw.

 

[F_R]

Re: Experts Needed - 55hp stalls at idle when warm.

The concept is that the choke solenoid has two windings. The first is activated by a thermal switch in the water jacket. When the motor is cold, the thermal switch sends voltage to the choke, holding it part way closed. When the motor warms up and the thermal switch opens, and the choke opens completely. The problem arises in warm weather and the choke is partially closed when it needs to be open, causing flooding. The modification puts both solenoid windings under the control of the manual choke switch in the remote. (Both need to be activated in order to get adequate choking for cold start).

 

[tashasdaddy]

Re: Experts Needed - 55hp stalls at idle when warm.

please let us know the outcome.

 

[imported_Archer]

Re: Experts Needed - 55hp stalls at idle when warm.

I will absolutely let you know. This has been a real phantom problem with this motor and I'm sure this post will help others. It sounds like you may be right on target with your solution. It does FLOOD very easily when warm and that would be why it doesn't start easily. If I sit and wait a while, it fires more easily.

 

[imported_Archer]

Re: Experts Needed - 55hp stalls at idle when warm.

I went to do the suggested modification only to discover that my choke only has one winding. I looked at the electrical schematic and it is not tied in to the thermal switch etc. What else can you guys suggest that I look for? Is it possible that the timing is off? If so, can I adjust the timing with muffs connected? Any additional suggestions are much appreciated!!!
Thank you.

 

[wavrider]

Re: Experts Needed - 55hp stalls at idle when warm.

Timing,

go to faq section and read joe reeves timing method to get your timing set correctly.

sounds like it could be float levels in your carbs set incorrect allowing flooding at low idle, at faster speeds carbs not flooding.

lync and sync could be off, timing may be retarded at idle and make hard starting.

 

[imported_Archer]

Re: Experts Needed - 55hp stalls at idle when warm.

Sorry for the delay in getting back to everyone. Okay, here is the skinny. I adjusted the linK & sync, it appears to be where it need to be. I got a timing light and it was way off, at least -4 below TDC. I adjusted it to approx. 3-4 degree advance. It idles great when I first put it in the lake and I get it warmed up after 2-3 minutes. After I shoot over to my fishing spot and come down to idle, it surges to 3500 RPM and eventually slows down to 1200 and then eventually stalls. After fishing when I go to start the motor (warm motor) it will not idle at all! When I drop the warm-up lever, it very quickly drop the RPMS and stalls. It starts quickly each time and I have to jam it in gear when the RPMs are low enough and hope that it doesn't stall and makes it to higher speeds where it runs perfectly.
I make sure that the bulb is hard, it is not the issue.

The coils look perfect, is there a way to check them and could that be the problem? Is this electrical? This only seems to appear when the motor is warm. Why does is surge when I come down from high RPM's. THe linkage is moving freely and not binding etc...

Thank you for any assistance.

 

[tashasdaddy]

Re: Experts Needed - 55hp stalls at idle when warm.

is the timing plate moving freely, could be getting hung up, or sticking. stalling is say idle rpms. may need to be adjusted.

 

[imported_Archer]

Re: Experts Needed - 55hp stalls at idle when warm.

I've tried all of the recommendations, thanks all. But I am still have issues with the motor.

1) When I run at a decent clip and then come down to stop and place the boat in neutral, the engine revs to over 3500 rpms!! I have checked linkage issues and binding and don't see anything. Could this somehow be related to my older issues of the boat not wanting to idle after it is warm.

Any direction here guys would be great as I am about to sell this motor and get out of boating. Unfortunately! Is it just a crappy engine and I should give in to it?

Help me

 

[ezeke]

Re: Experts Needed - 55hp stalls at idle when warm.

Just for reference, the motors that needed the choke solenoid modification were earlier models: the Service Bulletin (#1335) was issued in 1974 and most motors by 1977 did not have the system.

 

[tashasdaddy]

Re: Experts Needed - 55hp stalls at idle when warm.

is the cable pulling the throttle all the way back, is the timing plate moving all the way back? get some to drive and watch all this stuff.

 

[ezeke]

Re: Experts Needed - 55hp stalls at idle when warm.

The carburetor orifice sizes were changed on the 1979 55HP after the factory service manuals were published. You might want to check to see what sizes you are running.

pg. 2-2 Specifications Should read: High speed orifice plug....P/N 322907

Idle Oifice plug (top carburetor)... P/N 323151, hole size 0.045 (1.125 mm)
(bottom carburetor)....P/N 325827, hole size 0.044 (1.12 mm)

 

[imported_Archer]

Re: Experts Needed - 55hp stalls at idle when warm.

Possible Fix to this nagging problem!!!!

I have exhausted everything so I thought that I would go back to the basics. I went over the engine with a fine tooth comb and found an air line from reed assembly that connects to the carb intake cover!!!!

I haven't had a chance to get the boat on the water yet, but that must be the idle problem! My thoughts are I use the choke when cold so it doesn't affect the idle. When warm, the reeds aren't closing and I have difficulty starting and with flooding issues......

Experts: What does that hose do? Does it create a vacuum to close and open the reeds? What are the symptoms of it not being hooked up??

Dying to get the boat to the lake. Thoughts please.

Archer

 

[ezeke]

Re: Experts Needed - 55hp stalls at idle when warm.

The piston stroke creates the vacuum that opens the reeds.

The hose between the air silencer and the intake manifold is a drain hose, not an air hose.