1989 70 Johnson - Will Not Idle

[renegade]

I have rebuilt the carbs, replaced all the fuel lines, filters & spark plugs. Compression is good as well. Also, there are no needles to adjust on the carbs, all jets are non adjustable. When idling "in-gear" or "out-of-gear" the engine will studder a little, cough & stop (especially in gear I should mention). It sounds like it's not running on all cylinders when I advance the throttle to prevent stalling. I can also prevent stalling by choking with the key. After choking it, the process repeats itself in about 5-10 seconds, sometimes longer. I'm getting a little air in the fuel filter below the priming bulb (primer bulb has been replaced as well). Possibly an air leak, where could it be & could this cause that particular problem? Suggestions are much appreciated.

 

[JB]

Re: 1989 70 Johnson - Will Not Idle

You didn't mention the fuel pump, Renegade. That is probably where your trouble is, unless there is restriction/leak in the tank or a plugged tank vent.<br /><br />Overhaul the fuel pump.<br /><br />Good luck.<br /><br />Red sky at night. . .<br />JB

 

[almost retired again]

Re: 1989 70 Johnson - Will Not Idle

Just my thoughts Renegade, but if when you push in on yhe key it picks up then it's telling me that you still have carb problems. I would remove them again and pay particular attention to the low speed circuit behind the throttle plates and the intermediate circuits just in front of the throttle plates. If that don't work then do a sync& link adjustment; that wouldn't be a bad idea anyway.<br />Just my opinion

 

[petryshyn]

Re: 1989 70 Johnson - Will Not Idle

Air in the fiter is normal.<br /><br />>Does squeezing the primer bulb until hard, have any effect? If so, do a vacuum test on the inlet side of the fuel pump(between pump and filter) Anything over 5"HG suggests a restriction(plugged filter, crimped hose, poor tank venting, anti-spill valve)

 

[renegade]

Re: 1989 70 Johnson - Will Not Idle

Holy Smoke! This is great you guys respond so quick. Anyway, The one thing I haven't done was rebuild the fuel pump. Is it possible to get a kit for an '89 70hp Johnson? I had a 91 225 Johnson on my last boat and every Johnson/Evinrude dealer I spoke to said they did not make a rebuild kit for the fuel pump? Not the same motor though - might be a different story. Thank you so much, I really do appreciate the suggestions. You'll all be hearing from me again to either thank you for the Rx or for more suggestions.

 

[renegade]

Re: 1989 70 Johnson - Will Not Idle

In response to the other questions. The bulb is not soft while this is going on - atleast until recently. I just replaced the bulb 5 days ago. Before replacing the bulb, it would not firm up or pump gas to the engine. The new bulb does stay firm before starting and after. I have had the carbs off three times actually. This last time having them off I did pay special atention to the low speed jets and removed the little metal cover concealing the low-speed jets to make sure no dirt or whatever was present. I replaced the caps and put the carbs back on yesterday to go out in my boat today. Whammo - it did it again?

 

[ICEMAN]

Re: 1989 70 Johnson - Will Not Idle

As mention by almost retired again, if you pushed the key in and it picked up, I woldn;t go to the fuel pump yet, It sounds like your still having a carb problem. Take the front cover off so you can see into the carburetors. Start the motor and place two fingers across the front of the top carb opening. If it picks up, check that carb, if it starts to get worse, remove your fingers and let it recover, then try the middle carb and bottom. If one of them picks up, then I would pull that one and go thru it again, pull the low speed jet out and make sure there is nothing blocking the hole in it.

 

[JB]

Re: 1989 70 Johnson - Will Not Idle

Renegade:<br /><br />There are three carbs. The likelihood that all three have the same problem at the same time, after you have serviced them three times, is about zero.<br /><br />There is one fuel pump. You are not getting enough fuel. The pump has not been serviced. Everything else has.<br /><br />This does not require rocket science.<br /><br />Red sky at night. . .<br />JB

 

[renegade]

Re: 1989 70 Johnson - Will Not Idle

Rocket Science huh. Let me ask you this, then Mr. Rocket Scientist - wouldn't I be bypassing the fuel pump by priming the bulb to keep fuel in the carbs? A bad fuel pump would be more of a high speed problem of not keeping fuel in the carbs while having a soft bulb - not a low speed problem with a firm bulb, eh? That's my dissertation bud. I appreciate "constructive" criticism - not put downs.

 

[JB]

Re: 1989 70 Johnson - Will Not Idle

No put-down intended, Renegade. I was merely trying to get you to do the fuel pump rather than going back into your carbs a fourth time.<br /><br />If That offended you, my apologies.<br /><br />Red sky at night. . .<br />JB

 

[petryshyn]

Re: 1989 70 Johnson - Will Not Idle

Lets simplify the situation.....While operating the engine, "maintain" a hard ball by continualy squeezing it. If the problem goes away = fuel pump problem or restriction. If the problem still exists = carbs, ignition or engine, etc.

 

[renegade]

Re: 1989 70 Johnson - Will Not Idle

Thank you schematic. The bulb does stay firm as the engine is running - I'm going to guess it's gotta be some kind of restriction or timing issue. I'm also going to make sure all the butterflies in the carbs are all in sync (fully closed at idle). I just hate taking my boat to a mechanic - I don't trust any of them.<br /><br />Thank you for your suggestions.

 

[DJ]

Re: 1989 70 Johnson - Will Not Idle

Also, make sure you do not have any vacuum leaks. Check ALL of the little vacuum hoses running around the engine. Particularly those in the carb/intake area.

 

[renegade]

Re: 1989 70 Johnson - Will Not Idle

I readjusted the butterflies & replaced the VRO to a commercial "fuel only" pump & now she purrs like a kitten. Must have been a vacuum leak at the pump. Thank you to all that helped me through this.<br /><br />P.S. Cornwell - Bombardier does not manufacture a rebuild kit for VRO pumps - for your reference

 

[jegervais]

Re: 1989 70 Johnson - Will Not Idle

Actually, they do have kits available for SOME of the pumps. <br /><br />Kits are NOT available for '96 & newer pumps with a 438*** or 5000*** part number, but SOME individual components are. See the accessories microfiche, under fuel systems.<br /><br />There ARE kits for the older pumps, but a dealer would have to look in the 1997 (or older) accessories microfiche (again under fuel systems) or see tsb 2237. <br /><br />I guess some dealers either don't want to be bothered with it, or aren't smart enough to know where to look.<br /><br />-John

 

[renegade]

Re: 1989 70 Johnson - Will Not Idle

I think you're right - it seemed like the didn't want to bother with it. Then again, why would they when the can make $150 on a new pump. I called around and even went on the net searching for rebuild kits for my fuel pump to no avail. I kind of wanted to go the "fuel only" route anyway. Hopefully this pump will do its job for the remainder of the time I have this boat. Thanks for the feed back though.

 

[renegade]

Re: 1989 70 Johnson - Will Not Idle

'89 70hp johnson (J70TLCEM)

 

[JB]

Re: 1989 70 Johnson - Will Not Idle

Renegade:<br />You are welcome.<br /><br />Red sky at night. . .<br />JB

 

[joebone]

Re: 1989 70 Johnson - Will Not Idle

GO DOWN TO YOUR OMC DEALER AND BY A CAN OF ENGINE TUNER AND FOLLOW THE DIRECTIONS - DO IT A COUPLE OF TIMES AND THIS WILL MAKE THE THING RUN RIGHT - GASOLINE USED TO HAVE DETERGENT AND NOW IT DOESN'T - TCWII CREATED TOO MUCH CARBON AND IN BETWEEN TCWII AND TCWIII A LOT OF MOTORS GOT CARBED UP. ENGINE TUNER FIXES IT RIGHT.

 

[renegade]

Re: 1989 70 Johnson - Will Not Idle

I have the can in my garage I just need to use it. <br /><br />Also, the engine is overheating with the new thermostat I put in. All the fins are clear in the head (changed the head gasket as well) but does not over heat with it out. My mechanic says there were some models were the had to drill a hole in the head somewhere to release an air build-up in the block????? Sounds kinda far fetched to me - does anyone know anything about an overheating problem with an '89 70hp Johnson (model # J70TLCEM)?