140 Johnson Starting problems

[pj_elia]

I have a 1977 140HP Johnson Seahorse. I got the motor and boat this season. I've been using it all summer and until recently have had starting problems. Early in the season the motor was hard to start cold but after choking for awhile it would start and run well. Lately its been really hard to get going and would flood really easy. If I blew out all the cylinders with compressed air and carefully sprayed staring fluid in the carbs I could get it to start. It would then run fairly well the rest of the day. I checked for spark and I can not see any. I disconnected the red boot ignition fuse near the coils and jumped the starter and still got no noticeable spark. Also, the alarm in the controls is making a weird whistling noise which started yesterday 2 weeks after these problems surfaced. When I choke the carb for a while gas drips out of the carb. I never noticed it doing that in the past. <br /><br />I am dealing with a carb/fuel problem or an ignition/electrical problem. I must be getting some spark because I've been able to get the motor started after repeated drying the plugs and cylinders with air the last 3 times using the boat. <br />What do you guys think? I'm really out of ideas. I'd appreciate any help.<br /><br />Thank You,<br /><br />Paul

 

[OBJ]

Re: 140 Johnson Starting problems

Welcome Paul to iboats!<br /><br />First....we do NOT use any accelerant to start 2 stroke engines. There is no lubricant in the stuff. If you must use something....us some premix in a spray bottle.<br /><br />OK...first get some info on the engine....get a compression test on each cylinder. Good is considered above 90psi. But more importantly, the compression readings should be within 10 to 15% of each other.<br /><br />Check the spark...your engine spark on each cylinder should jump a 1/2" gap with a hot thick spark....like lighting.<br /><br />The fuse you disconnected won't prove anything. It's just a fuse in the power supply to the ignition switch. <br /><br />When was the last time the carbs were cleaned and overhauled? If you don't know....probably would be a good thing to do.<br /><br />The alarm horn may just be going south. Does it tone anytime the ignition switch is just turned to "ON"?<br /><br />OK Paul....let's start there. Fill in the blanks as you can....thanks.

 

[pj_elia]

Re: 140 Johnson Starting problems

OBJ,<br />Thanks for the invite. This site is great!!.<br /><br />The compression was checked earlier in the season and it had between 100 and 110 on each cylinder.<br /><br />I have been checking spark by inserting a metal rod into the plug boot and holding near a head bolt and I can't see a spark. <br /><br />The alarm used to just tone when the ignition went on until yesterday and now it tweats like a song bird.<br /><br />I don't know when the carbs were overhauled last. I had the motor serviced and checked out right when I bought it in May. The mechanic said everything was in surprising good shape as far as spark, the charging sytem, the water pump, compression, and the bottom end. He did not do anything to the carbs since the motor ran well then.<br /><br />Paul

 

[OBJ]

Re: 140 Johnson Starting problems

Check the spark again Paul only this time pull the big red plug apart on the engine, this is the one that connects the wire harness to the control box. Use the metal rod again and using a jumper to the starter solenoid, crank the engine and check for spark. Trying to narrow the field down by ruling out the key switch and stop circuit. <br /><br />And another set of compression readings won't hurt.

 

[pj_elia]

Re: 140 Johnson Starting problems

OBJ, <br /><br />I'll try that this afternoon. <br /><br />Thanks,<br /><br />Paul

 

[pj_elia]

Re: 140 Johnson Starting problems

OBJ,<br /><br />I pulled the plug and got pretty good spark. I reconnected and now I get good spark. One crank of the engine with a little choke and it fired right up cold. The plug was fully connected but I guess there must have been a loose wire or bad connection in the plug. The terminals inside plug looks farely clean. No corrosion. The boat starts and runs great now!!!! Any ideas where I lost my spark?<br /><br />Also, the alarm no longer tones except for an occasional tweet. Where can I get a replacement?<br /><br />Thanks Again,<br /><br />Paul

 

[Solittle]

Re: 140 Johnson Starting problems

Before you replace the alarm check to see if it is not telling you that your engine is overheating. You can check it by turning the ingnition switch to on and grounding the brown wire that connects to the temperature sender on the head. If in doubt replace the water pump (I would also repace the thermostats). It would be a shame to get the other problems sorted out and cook the engine due to overheating.

 

[pj_elia]

Re: 140 Johnson Starting problems

When I ground the brown wire the tone gets load and steady. The water pump is pumping. And the engine is only slightly warm all over.<br /><br />Paul

 

[Solittle]

Re: 140 Johnson Starting problems

Bet the alarm is OK but you have a weak or bad connection resulting in the whistling.

 

[pj_elia]

Re: 140 Johnson Starting problems

The alarm would sound with the brown wire removed. I check for a loose connection and it would still do the same. I bought a replacement alarm. The one for my motor the dealer wanted over $60 for. He found another alarm that sold for around $30. I bought that one and hooked it up. This alarm only has the purple ignition wire and a brown sender wire. No ground like the original. I believe it will work because the sender will ground when the temp goes up. The alarm is no longer making weird noises and grounding the sender wire sets the alarm off. When the ignition is turned on I don't get the quick tone I used to get with the grounded alarm but that's OK. <br /><br />I also bought the water pump kit. I have a stripped spark plug hole to deal with also. Other than that the motor and boat has been doing well for me. <br /><br /><br />Paul

 

[pj_elia]

Re: 140 Johnson Starting problems

I fixed the spark plug hole with an insert. We'll see how long that lasts. I'm still having trouble trying to start the motor. When I choke it for about 5 seconds, gas comes dripping out of the carb. Is that normal. When I pull the plugs they are very wet. When I check for spark, I now get a pretty good spark, not like before when I originally posted. It may not be as strong as it could be. Any ideas?? Again, when its started and warmed up, its pretty good but not perfect the whole day. <br /><br />Paul

 

[pj_elia]

Re: 140 Johnson Starting problems

Anybody have input on the gas coming out of the carb. Is the hole in the bottom right of the lower carb supposed to drain the extra gas. The plastic cover over my carbs no longer has the gasket. Should choking cause the flow of gas out the carbs? If not any ideas on what might be the cause? The primer bulb does get hard when I pump it. I think the needle valve is working.<br /><br />Paul

 

[Solittle]

Re: 140 Johnson Starting problems

Follow OBJ's recommendation to overhaul the carbs & use the shop manual.

 

[pj_elia]

Re: 140 Johnson Starting problems

Solittle, I figured that was going to be to plan. I fired her up this evening with out choking by sparying some gas behind the cover. It started right up. For some reason choking the motor cause it flood easily. Anyway, I must of done crap job repairing the spark plug hole because I could feel air coming out. The kit I bought used a combination reamer and tap. It was a REAL pain reaming out the hole. I pulled the head and the pistons and cylinders look GREAT. Not a lot of carbon and no signs of wear. This motor must have been rebuilt recently. Anyway, I'm waiting for a new used head to arrive along with a cowl seal and the correct OMC paint to give the motor a clean look.

 

[pj_elia]

Re: 140 Johnson Starting problems

Ok, an update. I replaced the head due to the bad spark plug hole. I went to run the motor and it would flood and not start. I checked spark and I was only getting good spark on the #2 cyclinder. VERY weak to no spark on the others. The following day, I swapped the coil leads on the power pack to check the coils. This time all cylinders were getting good spark. I plugged them back onto the spark plugs and it fired right with only a little bit of choking. It ran great the following day in the driveway also. So it appears my problem is intermittently weak spark. Interestingly, when I have weak spark, spark to cylinder #2 is still strong. Where should I start looking? Right now I have good spark and the boat starts and runs well. I scared to take it out for fear of not being able to start it.

 

[MCM]

Re: 140 Johnson Starting problems

Hi, power pack would probably be the most likely culprit.<br /><br />Mike

 

[pj_elia]

Re: 140 Johnson Starting problems

I agree it seems like the power pack but before I go and buy a new one, I want to make sure that there is not some loose connection I should be looking for. I thought if the power pack goes bad I won't ever get good spark.<br /><br />PJ

 

[MCM]

Re: 140 Johnson Starting problems

Hi, check this link, lots of good info on troubleshooting ign. problems.<br /><br /> http://outboardparts.com/omc/troubleshooting/trublshtinghlp.htm <br /> <br />Good luck,<br />Mike

 

[Goodoleboy]

Re: 140 Johnson Starting problems

I would suspect two possible causes for your spark problem,s.<br /><br />When you first disconected the big red connector and then got good fire to all cylinders and she started right up. <br /><br />Thats an indication that you have slight corrision in that plug someplace.<br /><br />Get a spray can of corrision remover from auto parts store and spray that plug real good mabey a couple or three times over a period of an hour or more.<br /><br />The other passible places were your connections of power pack and coils may have had poor ground connections. Clean those connections real good.<br /><br />You could have a bad power pack. But I wouldnt start buying parts until I was certian all connections were good and proper.<br /><br />Good luck!

 

[Solittle]

Re: 140 Johnson Starting problems

Don't forget to rebuild the carbs.