1980 100 hp evinrude runs erratic

[dixieray]

Misses, spits, or backfires and dies at idle in lake. On garden hose it runs away, dies suddenly in nutural, and no start lever. Tack. not working. Won't idle at all. Ran ok at faster speeds in lake. but coughs and dies when trying to put in gear.<br /> New carb kits installed, gas new to carbs.<br />What gives?????????????????????????<br />100 plus for compression and has sparks on all 4 plugs.

 

[jimtodd72]

Re: 1980 100 hp evinrude runs erratic

Sounds like a possible ignition problem. Many times, these problems aren't apparent when testing engine on trailer but when the engine is in the water, the conditions working on the engine (backpressure, etc.) manifest themselves. See what type of ignition you have on this engine, probably a Type II CD Flywheel Magneto, and you will need to start troubleshooting. Let me know what you find out.<br /><br />Jim

 

[dixieray]

Re: 1980 100 hp evinrude runs erratic

Looks lake a cd 4. I checked ohms on charge coils,Sensor coils, and Ignition coils. Did find Stop on key sw. with low reading due to corrosion in big plug, cleaned.This did help some with runaway, now problem is the miss and die at idel. Timing lignt shows loss of some spark on one plug and changeing ignition coil was no help, may try powerpack.<br />Seems like more than one cylinder to me.

 

[jimtodd72]

Re: 1980 100 hp evinrude runs erratic

Also, check your plug wires and boots. A small crack in either could cause an arc to the closest ground and cause that cylinder to miss. I had a crack in the boot of one of my wires last year which was causing an arc to the flywheel and rough running. I only found it after cranking the engine near dark and seeing the arc.<br /><br />Jim

 

[dixieray]

Re: 1980 100 hp evinrude runs erratic

Did't see anything after dark, past experience with a bad coil, plug wire, and powerpack, it would just run a little slower and not die. I pulled off two plug wires and it runs ok at a fast idle. Pulling off one plug wire at a time will not stop problem. Either it's more than one problem or something????? It's like one cylinder fires early and stops rotation, not like a miss and free wheeling?????????

 

[Chum Slick]

Re: 1980 100 hp evinrude runs erratic

Had similar problem with 1980 115 Johnson. Drove me nuts trying to troubleshoot. Finally found flywheel key was broken causing the timing to jump erratically.

 

[dixieray]

Re: 1980 100 hp evinrude runs erratic

Thanks, flyweel key is ok, but it does seem like timing is changeing, I am thinking the powerpacks are interfering with each other even though they ohm check ok. Hate to buy one just for a check.

 

[Joe Reeves]

Re: 1980 100 hp evinrude runs erratic

Dixieray.... Hopefully you've found the cause of your problem by now, but if not, I'll put my two cents worth in here.<br /><br />The tach not working could be one of three things...a broken wire, a faulty tach, or most likely a blown faulty shorted rectifier. The rectifier will blow if you connect a battery backwards momentarily or hook up a battery charger backwards. In short, it will not tolerate reverse polarity.<br /><br />The spitting back, dying out at idle is usually caused by one of three (or all) things. Either the carbs were not cleaned thoroughly and something is still clogging a passageway, or the carbs are opening too soon (the scribe mark is not aligned with the center of the carb roller when the carbs start to open), or the linkage between the carbs is adjusted wrong (throttle valve on one carb open, other is closed). Hope this helps you out somewhat.

 

[dixieray]

Re: 1980 100 hp evinrude runs erratic

Thanks, Ihaven't worked on tach. yet, but will now. It's not in my book. Boath carbs 4 burrels tot. are closed with marks on cam and follower aligned. They open together. all looks good. I sprayed electroclean through all jets and pasageways in carbs. Had them off 4 times now and can't see any thang wrong. Spraying starter fluid in lower carb a lettle at a time stopes the missing so i think is fule porb. Ordered srark tester and peak voltage tester anyway shoould get it soon. Maybe you could tell me the passage in carbs for idle not clear in my book (clymer) book does not have arrow for the idle air bleeds,??? Bottom of carbs is like the early try-jet. There are no adj needles of any kind. I don't have the plate on top of carbs. I don't have an idle chamber. bought motor in canada 1981. still no progress????????????????????????

 

[Joe Reeves]

Re: 1980 100 hp evinrude runs erratic

Dixieray.... Have the carb face plate offd. Run the engine and stick two fingers into the carb intake throatc, one throat at a time. If the engine smooths out or the rpms increase when you restrict a certain carb throat, that's the problem area. It could be that a jet and/or passageway requires cleaning out with a piece of mechanics wire. I run into that quite often. I'm assuming that you removed the high speed jets from the float chambers (4 jets). If not, remove and clean them with a wire. Run a wire through all the passageways as a cleaning solution often misses what it shouldn't.

 

[ob1jeeper]

Re: 1980 100 hp evinrude runs erratic

Just fixed the IDENTICAL problem with my Johnson 235... Turned out to be the small crankcase vent hoses, which vent the crank, via the carbs... give the hoses a good look, and make sure to check the function of the crankcase check valves too...

 

[dixieray]

Re: 1980 100 hp evinrude runs erratic

Ok may not get it done til late Monday, motor runs ok at mid & high speeds, I did't pull the frezze like plug out, but saw no gum or dirt anywhere in carbs look like new. will ck futher. Thanks

 

[dixieray]

Re: 1980 100 hp evinrude runs erratic

Choking the top left carb (2 fingers) makes it run better, I have cleaned the carbs again & found nothing. Ran wire through all jets. ob1jeeper------I have pressured checked the small hoses with electrowash, they seem good, but it must be sucking air from somewhare. Do the crankcase check valves feed the small hoses and how do I check them????????????

 

[dixieray]

Re: 1980 100 hp evinrude runs erratic

It will be awhile before i can run motor again as I beleave I have busted two of 4 Reed recirulation valves (check valves, plastic with screens, maby) by cleaning them with a wire. Insted of one way passage I now have flow in boath diredtion. Omc item will take a while to get them!!!!!!! Do i need them what do the do? Is it necessary to have them?

 

[Joe Reeves]

Re: 1980 100 hp evinrude runs erratic

Dixieray.... You just said "Choking the top left carb (2 fingers) makes it run better, I have cleaned the carbs again & found nothing".<br /><br />Okay, if you're standing in front of the engine, in front of the carbs, you're speaking of the carb throat that feeds #1 cylinder. The port slow speed jet on that side which is in back of a small aluminum screw, to the rear of the top carb body, just above the float chamber gasket should contain a clean small jet with a .028 fuel passageway opening. If so (and if passageway opening is absolutely clean), enlarge that opening to .031 (but no larger than .031!)<br /><br />That should cure your problem. Let me know.

 

[dixieray]

Re: 1980 100 hp evinrude runs erratic

I wish I could but, My carbs has a led shot there and no screw. There are no screws abouve the gasket anywhere. I have four screws and jets in the bottom of the fuel bowl of carbs only. Also 2 idle air jets in top frount of carb throughts. I did find a split small hose on connection to crank case. This came from reed valve of same carb I choked down with fingers, just behind carb. Could this have an effect? Ran wire through 2 valves and will have to get them before I can test it. I thinik the recirulating valves are check valves small palastic , screened things. Will post when I get them.

 

[Joe Reeves]

Re: 1980 100 hp evinrude runs erratic

Dixieray.... Whooops, sorry, I was thinking of a earlier model carb. Happens every now and then (old age ya know). Those upper idle air bleeds would cause the same problem as per the s/speed jets that I mentioned, excepting that instead of enlarging that #1 cylinder idle air bleed, you would want to close that air passageway down some which would force more fuel into the cylinder at idle. The one in there right now should have a .034 passageway in it (part #324025). Try closing it down to a .031 (part #318823). For a reference, various size idle air bleed jets (8/32 thread size) would be: 324652=.026, 317474=.027, 322936=.028, 322776=.029, 317473=.030, 318223=.031, 320016=.032, 320015=.033 .

 

[dixieray]

Re: 1980 100 hp evinrude runs erratic

Thank you very much, next run time I will put my finger over the jet & if sat. will try a .026 it has .028 now, thanks again.

 

[dixieray]

Re: 1980 100 hp evinrude runs erratic

FYI. Motor ideling perty goodnow. Think it was small house creck someone mentioned above , but mine seems to go from reed valve block to different cylender. Replaced ones I ran wire through but broke one off and had to remove reed block to help clean it out, big mess, I also broke fule manafold and had to replace. Put all back togeather and spitting and dieing quit, with a little miss. Stevans spark tester came in today and I had no spark on 2 cylenders sometimes. Had required voltage from pawerpack , used the Stevans dva adapter so replaced 2 I. coles, even ohm ck. was ok. So far cost $200 and counting. Now I plan to replace the transom board on my Starcrafe alum. boat any suggestions will be greatley apresiated.

 

[dixieray]

Re: 1980 100 hp evinrude runs erratic

STARTED SPITING AND DIEING AGAIN...........THIS MUST BE A 1ST. SAW BUTTERFLY IN TOP CARBS VIBERATING AND HELD IT STEADY MOTOR RAN GOOD. TIGHTENED SPRING ON BUTTERFLY ONE HALF TURN AND CURED PROBLEM. tHANKS ALL.