Engine stalls at idle and when under load.

[Stinkytoots]

I have a 1979 Evinrude 85hp model #85999r. Over this winter I rebuilt the lower unit, replaced both shifter cables, cleaned and rebuilt carbs to spec, replaced spark plugs, replaced fuel lines and rebuild the fuel pump. After completing these items, my 1st time taking it out it purred at idle but still died under load if the engine wasn't warm. Once the engine was warm it seemed to be a finely tuned machine.

Wile on a fishing trip last week, the starter bolts stripped out leaving me on the lake with my boy as I used my foot to keep the started on place so we could get back to the cabin. That day I used a Hele-coil kit and replaced the starter.
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Since then the engine will not stay running warm or cold at idle rpm's 8k. last year I had the problem of the engine dying when I put into gear.

Should I increase the idle rpms? What can I do to prevent the engine from dying when placed into gear? I was originally thinking it was a fuel problem, thats why I rebuild the carbs, the fuel pump and replaced the fuel line.

 

[BonairII]

What rpm is it currently idling at(check manual for recommended idle rpm)? Did you make sure to completely clean the carbs(under welch plugs, pulled/cleaned jets, etc etc)?

I'm guessing that idle rpm(on muffs) should be around 1100 rpm(or 900 rpm with leg submerged).

Always check "vitals" first. Compression, good quality spark(jump 7/16ths air gap). If motors perks up when choke is bumped...troubleshoot the fuel system.

 

[coolbri70]

I have the same motor, it does the same thing if I try to take off before it warms up. thought it was normal, I just been letting it run for a half minute or so before I try to put it in gear after that runs great

 

[emdsapmgr]

It may not be firing on all 4 cyls. It will sound good when running on the trailer, when only 2 or 3 plugs are firing, so check for spark. Make sure the engine is well warmed up, as weak ignition components tend to run well when cold, then not when the engine warms up to normal operating temps. The idle is set to 650-700 rpm's when the boat is floating normally in the lake and it's in forward gear. You can't set it when it's on the trailer.

 

[Stinkytoots]

"What rpm is it currently idling at(check manual for recommended idle rpm)? Did you make sure to completely clean the carbs(under welch plugs, pulled/cleaned jets, etc etc)?"
I did clean the cabs and even let them soak in solvent. Then I took and blew it out with the air compressor. The carb kit came with new welch plugs and cleaned jets and all.

"Always check "vitals" first. Compression, good quality spark(jump 7/16ths air gap). If motors perks up when choke is bumped...troubleshoot the fuel system."
Compression is good and with in tollerence, spark is good and gaped. motor bogs and sounds like crap when choke is left on.

At the start of the season I could start it and drop the start lever all the way down and it would still purr. I can still do that, it just dies as the rpms drop after about 30 sec.

I am going to take it out on the lake here in a few, at that point someone I was talking to said put in gear and adjust the cables so the rpms are at 1100 like you did and said that my RPMS should'nt be that low. I will post update here when I get home.

Thank you all.

 

[Stinkytoots]

"What rpm is it currently idling at(check manual for recommended idle rpm)? Did you make sure to completely clean the carbs(under welch plugs, pulled/cleaned jets, etc etc)?"
I did clean the cabs and even let them soak in solvent. Then I took and blew it out with the air compressor. The carb kit came with new welch plugs and cleaned jets and all.

"Always check "vitals" first. Compression, good quality spark(jump 7/16ths air gap). If motors perks up when choke is bumped...troubleshoot the fuel system."
Compression is good and with in tolerance, spark is good and gaped. motor bogs and sounds like crap when choke is left on.

At the start of the season I could start it and drop the start lever all the way down and it would still purr. I can still do that, it just dies as the rpms drop after about 30 sec.

I am going to take it out on the lake here in a few, at that point someone I was talking to said put in gear and adjust the cables so the rpms are at 1100 like you did and said that my RPMS should'nt be that low. I will post update here when I get home.

Thank you all.

 

[Stinkytoots]

"I have the same motor, it does the same thing if I try to take off before it warms up. thought it was normal, I just been letting it run for a half minute or so before I try to put it in gear after that runs great"

Currently even after warming up it dies. What RPMS is yours running at idle?

 

[Stinkytoots]

I have the same motor, it does the same thing if I try to take off before it warms up. thought it was normal, I just been letting it run for a half minute or so before I try to put it in gear after that runs great

Currently even after warming up it dies. What RPMS is yours running at idle?

 

[coolbri70]

just below 10, at idle. mine does better with new plugs, or if i clean them, especially if it idled a lot at the ramp last time out

 

[Stinkytoots]

Well after starting it tonight the engines rpms was jumping and falling in an odd manor, so I checked the engine plugs while it was running by twisting them and nothing, then I started to pull them and see if there was a difference. I am unhappy to say that I am currently only running on 2 cylinders. I am going to order Power packs and wires and see if I can get things back to all 4 cylinders. It seemed really ruff tonight in comparison and there was gas in the exhaust (floating in the water when the engine stopped).

Is there anything else anyone would recommend that I replace or check?

 

[SigSaurP229]

Before spending the money to order swap the power packs, if the dead spark follows the pack then it is a safe bet that the pack has failed, if not then further diagnosis is required. I would swap ignition coils as well. Those are the easiest and quickest diagnosis.