77 55 EVINRUDE IDLING PROBLEM

[praetor]

Hi all.. I've an 1977 55 Evinrude.. When I start the engine it idles very smooth as an 4-stroke engine.. But, when it pass for 3-5 minutes idling, (when engine becomes hot), it begins to sputtle and dies.Before motor stopped if I choke momentarly it begins to idle normally for 5-10 second and if don't re-choke again motor stops..All time I use fresh gasoline/oil, new spark plugs.. very good and blue sparks.. I newly rebuilt carburators and also changed the fuel pump. But, I can't solve this idling problem.. Do you have any suggestions? Thanks from now ..

 

[praetor]

Re: 77 55 EVINRUDE IDLING PROBLEM

Hi all.. I've an 1977 55 Evinrude.. When I start the engine it idles very smooth as an 4-stroke engine.. But, when it pass for 3-5 minutes idling, (when engine becomes hot), it begins to sputtle and dies.Before motor stopped if I choke momentarly it begins to idle normally for 5-10 second and if don't re-choke again motor stops..All time I use fresh gasoline/oil, new spark plugs.. very good and blue sparks.. I newly rebuilt carburators and also changed the fuel pump. But, I can't solve this idling problem.. Do you have any suggestions? Thanks from now ..

 

[Tom Scully]

Re: 77 55 EVINRUDE IDLING PROBLEM

Getting the engine to idle right by choking it indicates a fuel delivery issue. You're not getting enough of it.
Try spraying some pre-mix thru the carb throats, if it keeps running that will verify that it's a fuel delivery issue.
Also try pumping the primer bulb while its about to die, that will verify if the pump is operating properly.
If you have a fuel pressure gauge, measure the pumps output.
Check the float levels.

 

[praetor]

Re: 77 55 EVINRUDE IDLING PROBLEM

I'm sure that the problem isn't from the fuel pump because this is the 3rd pump I replaced .. I tried also to pump the primer bulb but nothing is cahanged, engine is died also is floaded..

I want to take your attention to one think is [colour=that problem occurs][colour=null]only [colour=when engine becomes hot][/colour](means after 3-5 minutes after starting )

Thanks for your suggestions

 

[praetor]

Re: 77 55 EVINRUDE IDLING PROBLEM

I'm sure that the problem isn't from the fuel pump because this is the 3rd pump I replaced .. I tried also to pump the primer bulb but nothing is cahanged, engine is died also is floaded..

I want to take your attention to one think is that problem occurs only when engine becomes hot (means after 3-5 minutes after starting )

Thanks for your suggestions

 

[praetor]

Re: 77 55 EVINRUDE IDLING PROBLEM

no other suggestions??:'(

 

[Tom Scully]

Re: 77 55 EVINRUDE IDLING PROBLEM

Will it idle with the choke on continuously?
Will it idle with the chokes partially closed?
What did the pulgs look like? Old -vs- new? Color?
Does it run well above idle under load?

Did you check spark after it's warm? (3-5 min).
It's possible that the power pack is failing after it heats up.
Try running it with the red cannon plug to the boat disconnected.

 

[hamburgerman]

Re: 77 55 EVINRUDE IDLING PROBLEM

See what it does with the cover off. Could be exsaust backing up inj the shroud . (I had this problen)

 

[praetor]

Re: 77 55 EVINRUDE IDLING PROBLEM

Tom, I tried everything you said.. When I pump the primer bulb nothing is changed.. When I choke continously motor is fouled and stopped.. I also changed powerpack and nothing is changed too. But, I don't like the spark from the second cylinder. The problem can be caused from the coil?? Can the problem caused from the second cylinder that there's no proper spark and from that cause cylinder don't work properly and the fuel pump don't work properly since poor working of cylinder creates poor compression?? Any suggestions??

 

[praetor]

Re: 77 55 EVINRUDE IDLING PROBLEM

no suggestions??:'(

 

[fireman57]

Re: 77 55 EVINRUDE IDLING PROBLEM

Have you checked to make sure that it is not overheating? Place a couple of fingers on the head when it does this. If you can hold them on there for six or seven seconds without getting the poo burned out of you then it is okay. If it is not overheating then hook up a timing light and check the spark on all cylinders when it does this. If you have a weak spark on one cylinder then remove and swap coils with a known good sparking cylinder and see if the problem follows.

 

[praetor]

Re: 77 55 EVINRUDE IDLING PROBLEM

thanks fireman.. I replaced ignition coils with the original spare parts.. Nothing's changed I did what you said.. No, I can't hold my fingers. But, water stream looks great and powerfull. What I have to do now?

P.S: Engine sputtered when It was hot before.. Now, it does all time. why?

Thanks for your replies from now

 

[fireman57]

Re: 77 55 EVINRUDE IDLING PROBLEM

You have to inspect/change the water pump. while you have the lower unit off use a 1/2" garden hose and clamp it to your water tube and let the water fly. If you have a blockage it may remove it. You might need (i would) to take your thermostat cover off and remove the tstat and look behind it for any crud, old gasket, or sealer that will block it. Might as well put a new stat in. Run your hose again with the stat out to flush anything else that is there. If you can find a 3/8" nozzle you can put it in the water jacket by the tstat and flush through the head too.

 

[praetor]

Re: 77 55 EVINRUDE IDLING PROBLEM

Thanks again fireman o.k.. I took off the thermostat. I controlled it.. It perfectly works. But; there was any fur on the thermostat. I cleaned it with spirit of salt. Now, it works I can put and hold my fingers for about 10 seconds.. ( I counted )..

Now, stopping problem seems like ended.. Unfortunately, sputtiring is standing. Can you stipulate why??

 

[fireman57]

Re: 77 55 EVINRUDE IDLING PROBLEM

You may have missed something in a low speed jet in one of your carbs or picked up new junk from your fuel tank. Put and inline filter on to prevent a further episode. I just use a cheap automotive on for this, aroung two or three bucks. You may have a cracked fuel line from the tank or to one of your carbs. Where the tee is for the fuel line to split to go to the separate carbs is a prime place for an air leak. You might consider replacing them as it is inexpensive and they probably need replacing if they are original. Sounds like you are pulling a little air from somewhere you shouldn't be and the fuel lines are always the first suspect. Are you sure that your vacuum lines to the carbs are clear? Can you blow throught them? Are they loose or cracked anywhere?

 

[praetor]

Re: 77 55 EVINRUDE IDLING PROBLEM

Thanks fireman yesterday, I tried my motor with the garden hose and adapter on the trailer.. It was sputtering but didn't stop. Today, I went to seaside and bring it to sea.. Unfortunately, motor idles rough and stopping at the idle. But, after the fast idle motor is working very clear and perfectly accelerate.. exhaust relief, water outlets also are very clear. No burned oily gas deposits.. I guess, it means that there is no problem neither from the ignition nor from the fuel.. I don't use its original tank rather I am using mine 1998 15 Evinrude's plastic tank and its fuel line.I looked to the carburators..( I newly replaced the small hose between them) .. , II can't see any cracked zone.. All seems like spotessly clean;I don't know what will I do My holiday is passing with this motor problem.. I can trust it to put ot to sea..

 

[Theoutdoorsman]

Re: 77 55 EVINRUDE IDLING PROBLEM

If indeed you have an air leak in the fuel delivery, I've heard of using a can of WD-40, spraying in precisely selected areas around the fuel lines, carbs, conections, and what-not, to aide in locating the leak. The engine should momentarily straighten out which would indicate that you have located the source of the leak(s). You might get confirmation from some of the experts here before attempting this. But I'm almost sure it's a common practice.Just a thought........Good luck!!!...........ALAN

 

[fireman57]

Re: 77 55 EVINRUDE IDLING PROBLEM

Check the fuel line where it plugs into the engine. Behind it inside your cowling is a hose that takes it to the fuel pump then hose that goes to aT and splits into a hose for each carb. Make sure that none of these have any cracks in them. If they haven't been replaced then do it and make sure that they are clamped on the nipples well so they can't pull any air at all. If these are all fine then when you are on the water you may need to adjust your idle up a little. When running on muffs in the driveway there is no back pressure like there is in the water. I believe that you should be around 700rpms in the water for you idle.

 

[praetor]

Re: 77 55 EVINRUDE IDLING PROBLEM

Yesterday, I tilted motor, I leave the fuel hose attached to engine. Today, I saw avery little fuel leak behind the carburator( only when motor is tilted). Is it a fault? This possible pirate suction can be from the leaking point?

 

[fireman57]

Re: 77 55 EVINRUDE IDLING PROBLEM

Very well could be. If the gasket behind the carb is leaking then it will pull air in when running, not let gas out. This would cause exactly the problem you are having. Replace it and find out. Make sure that your carbs are on snugly but don't overtighten them as they are only aluminum.