'94 70HP EVUNRUDE FRUSTRATION!

[SCOTTRIPPER]

HI GUYS, I'VE GOT A 94 70HP EV. WHEN I FIRST START UP, IT IDLES FINE,BUT AS SOON AS I PUT IT IN GEAR IT STALLS. AFTER 6-7 ATTEMPTS IT FINALLY RUNS PAST 1500 RPMS AND SEEMS TO RUN FINE UNTIL THE NEXT TIME I SHUT IT DOWN. THIS IS ESPECIALLY FRUSTRATING AT THE BOAT RAMP. MY FUEL BULB IS BRAND NEW, AND SO ARE MY PLUGS. ANY IDEAS? THANKS.

 

[Dhadley]

Re: '94 70HP EVUNRUDE FRUSTRATION!

There's lots of things to consider but the first thing that comes to my mind is carbs. Clean them and install good kits. You mentioned plugs. Which ones did you put in? What octane fuel? Does the motor smoke excessively? VRO or premix?<br />Good luck!

 

[JB]

Re: '94 70HP EVUNRUDE FRUSTRATION!

Hey, Scott. Does your controller have a "warm up" control to raise the idle speed during warm up? My first reaction would be to adjust the idle speed a bit higher, but I defer to DHadley,s experience. I have had 2 OMC 70's, and after I removed the VRO they were the best motors I ever had.<br /><br />Good luck.<br />JB

 

[SCOTTRIPPER]

Re: '94 70HP EVUNRUDE FRUSTRATION!

THANKS FOR THE REPLY. THE PLUGS I PUT IN ARE THE OMC RECOMMENDED CHAMPIONS, BUT THE PROBLEM WAS THE SAME BEFORE AND AFTER REPLACING THE PLUGS. I DON'T THINK I HAVE THE WARM UP CONTROL. I'LL TRY INCREASING THE IDLE SPEED TONIGHT AND SEE WHAT HAPPENS ON THE WATER. I'VE DISCONNECTED THE OIL INJECTION SYSTEM AND AM USING PRE MIX W/93 OCTANE FROM THE MARINA PUMP @50:1. THERE IS PLENTY OF WHITE SMOKE WHILE IDLING AND THE EXHAUST SMELLS LIKE IT WOULD IF A CAR MOTOR WERE RUNNING RICH. IS THERE ANY DANGER IN REDUCING THE OIL MIX SLIGHTLY? ANY HELP IS GREATLY APPRECIATED, IT'S MY FIRST BOAT.<br />THANKS AGAIN,<br />SP

 

[SCOTTRIPPER]

Re: '94 70HP EVUNRUDE FRUSTRATION!

JB,HADLEY - OH YEAH, MY VRO IS STILL HOOKED UP (HOSES,ETC.) BUT THE ELECTRICAL CONNECTIONS ARE DISCONNECTED. IS IT POSSIBLE THAT EXTRA OIL IS BEING VACUUMED INTO THE MOTOR WITHOUT THE ELECTRIC HOOKED UP?<br /><br />THANKS AGAIN,<br /><br />SP

 

[JB]

Re: '94 70HP EVUNRUDE FRUSTRATION!

Hey, Scott. If there is oil in the VRO tank you could well be getting extra oil injected. If there isn't you may be getting air mixed with your fuel. The VRO pump is operated by crankcase pulses, just like the fuel pump on older systems. The electrical wiring stuff is mostly for throttle position sensing, warning horns and indicator lights, etc. Disconnect, and plug, the oil inlet either at the pump or at the case. Do not try to use a fuel/oil mix leaner than 50:1. Smoke on a cold start is normal. Once you get things settled remove the oil tank, hoses, etc. but hold onto them. Some future owner may want them.<br />Good luck.<br />JB

 

[SCOTTRIPPER]

Re: '94 70HP EVUNRUDE FRUSTRATION!

THANKS, JB! I DISCONNECTED THE OIL INLET LINE AND PLUGGED IT AND RAN THE MOTOR FOR A WHILE, STOPPED AND FISHED FOR A WHILE, AND IT RAN FINE ON START UP AND RAN FINE AFTER BEING PARKED AT THE RAMP. I HAD FORGOTTEN WHAT IT WAS LIKE TO ACTUALLY DRIVE ONTO THE TRAILER. I THINK I WAS BURNING XTRA OIL. THANKS AGAIN!<br /><br />SP

 

[tinhog69]

Re: '94 70HP EVUNRUDE FRUSTRATION!

I think I have a problem that is like yours. My engine stalls when I put it in gear and try to advance the throttle. After I get it going (past 1500 rpm and 3 or 4 trys) and run it around the lake it is ok unless I shut the the motor off for 5 minutes or more. Then the problem is back again. It is a Johnson 70. Did your problem with your motor come back after it cooled after 5 or more minutes?? <br />I already put new plugs in it, adjusted the idle mixture and set idle. A boat shop looked it over and thought they had the problem fixed. But I still have it. It doesn''t seem to smoke that much now.<br /><br />I was thinking of rebuilding the carbs unless you think that disconnecting the oil injection and adding oil directly to the gas would be a better thing to try.<br /><br />thanks

 

[magnum28139]

Re: '94 70HP EVUNRUDE FRUSTRATION!

hi scott, glad that you seem to have your 70 hp idle problem's straightened out. I have a 1994 70 hp evinrude myself and it seem's that we are having the same problem's.Like you I have change the plug's with no noticeable result's. I had a boat machanic disconnect the vro and started mixing my gas/oil to see if it would help.no luck so far, think I'll see if he blocked off the oil pick up line to where it is'nt sucking air . maybe that is the problem. thanks to every one out there, It's a big help to come to this site and work on your boat....magnum...

 

[Andrew Brierley]

Re: '94 70HP EVUNRUDE FRUSTRATION!

Hi Guys, I know I am responding to an old post but I have the same problem and there is no resolution on the site. Did any of you solve it.<br /><br />I have a 1980 70hp Johnson, It starts easy as pie but it won't stay running until it is very warm. I already have the idle set very high but even that does not help when it is a little cold. As soon as I put it into gear it stalls. Boat yard mechanic told me he fixed it but all he seems to have done is increase the idle, he balance the carbies also. It idles fine out of the water, I am guessing this is because there is no back pressure on the exhaust.<br /><br />The motor does have lower compression on the middle cylinder (125 - 90 - 125)but I don't know that that would have a major influence on the idel problem. I am running premis at 50:1.<br /><br />Once you get it into gear it runns really really well for a motor with a compression problem.

 

[Beaux]

Re: '94 70HP EVUNRUDE FRUSTRATION!

ModCat-<br />you have slightly different situation. I would deCarb the motor first and see if you can get improvement in your compression numbers. Also want to check for air leaks in your fuel system (tank/hoses). Do a quick search on decarbing on this site. <br /><br />When was last time your carbs were cleaned? Sync-n-linc wont help much if the carbs are dirty. <br /><br />Be careful about having idle set to high....you dont want to try to solve one problem (stall) and end up creating another one (lower unit wear/failure). Good Luck

 

[clanton]

Re: '94 70HP EVUNRUDE FRUSTRATION!

Modcat, the cylinder with 90 lbs compression is too low, if it does not come back up with a decarb, I would remove the cylinder head, or bore scope the cylinder. I think you will find a bad cylinder/piston.

 

[Andrew Brierley]

Re: '94 70HP EVUNRUDE FRUSTRATION!

Thanks for responses Guys. The head was off recently to check why compression was so low. The result was that the centre cylinder had slight burn damage from an incident previoous to my purchase. The mechanic suggested that in light of the motors age and the fact that it had more then enough power in its present condition that I should not spend money on it at this point.<br /><br />Since I posted my initial reply I have removed about 2 meters of unnecessary fuel how and car style fule filter. I also replaced the coupling onto the fuel tank from the fuel hose. This I hoped would fix the problem, it di not.<br /><br />The next thing I tried was to pump the fuel bulb until hard, the motor appeared to run smooth at idle as a result but it is hard to prove as I had already lifted the idle up and the motor was warm. When I go the boat home and flushed the motor I had to drop the idle back a couple of turns as it was revving its ring out!<br /><br />The next time I go out I will pump the bulb hard and see how it goes while maintaining pressure to the bulb. If this works then I think I will replace the Fuel Pump. I will also ghet some carby clean as suggested and try that.<br /><br />I bought this boat with no knowledge of baoting or how to run and use an outboard. Is it standard practice to pump the fule bulb before starting? The motor has always started first time without doing this, even if the carbies have been run dry so I hjave always assumed this was not necessary?

 

[Solittle]

Re: '94 70HP EVUNRUDE FRUSTRATION!

Many a boater has run his battery down trying to start his (or her - sorry gals) motor when a squeeze or two of the bulb would put the fuel where it is supposed to be. I do it every time if the motor has been off for over 15 minutes or so.

 

[Andrew Brierley]

Re: '94 70HP EVUNRUDE FRUSTRATION!

Ok, Last Night I started the motor, started ok as usual then stalled.<br /><br />I squeezed the bowl a couple of times and started again, it ran slightly better but still stalled, it was stone cold so I can accept this. <br /><br />Started again after another couple of squeezes and it ran ok for a minute then started to stutter, I tried the bowl again and it was soft again so squeezed a few more times and was able to keep the motor running. Every third squeeze I can compress the bulb almost all the way.<br /><br />The more I squeeze the more fuel start to leek out of the coupling where the fuel hose connects to the fuel tank.<br /><br />On the way home today I will purchase a new coupling and see if that is my problem. I would not have thought an air leak could cause so many problems. Why does the air leak not affect the motor at intermediate and fast speeds?<br /><br />I Will post my findings tomorrow.<br /><br />Any other advise welcome but I think I have seen something similar to this in another post so I will do a search for it .

 

[dpminc]

Re: '94 70HP EVUNRUDE FRUSTRATION!

Just thought I would add to this thread, a very common reason for poor idle, and off idle bog on omc 3 cylinder in-lines, a bad thermostat. These engines are very picky about operating temp. Replace the thermostat and check the springs, and overflow valves(49cid only). I have dealt with so many "Ive had the carbs rebuilt,cleaned adjusted etc etc from every shop in town" problems, and all but two of them were cold engine temps due to bad thermostats or deformed valves, or broken bypass springs. check them out. As for the comment about "a slight burn from previous damage" in an earlier post: This can cause poor idle quality even if the motor seems to run ok at WOT. This is because the piston skirt, and very possibly the bottom ring are damaged causing poor crankcase pressures at low engine speeds.

 

[Andrew Brierley]

Re: '94 70HP EVUNRUDE FRUSTRATION!

I agree with you on the poor crankcase pressure being a possible cause but due to the fact that it idles for a short while and then stops I don't think that is the cause. Crankcase pressure would more likely result in constant poor idle, but I could be wrong. (I usually am <br /><br />I changed the fule hose fittings last night and after that the bulb was able to be squeezed unitl very hard, twice then it burst spraying my face with fuel (spit spit) I have now but a new fule bulb on as well.<br /><br />The engine started first time as usual. It seemed to idle ok but it never really has too many problems idling out of the water anyway. I won't really know until I put it in the lake on the weekend.<br /><br />Wish me luck, thankyou everyone for your help so far.

 

[Andrew Brierley]

Re: '94 70HP EVUNRUDE FRUSTRATION!

Ok, took her out on the weekend and she definately started and ran easier but she still coughs and stops when brought down to idle. The new fuel bowl and couplings have made a noticable difference.<br /><br />The only item left now is the Carbies, so I pulled them off yesterday.<br /><br />Now I need some help here guys. I know next to nothing about carbies. I found the main jet at the bottom of the float chamber. Where are the others? How many jets are there? I could not see any mixture adjustment screw? I don't want to pull the whole thing down unnecessarily and risk loosing bits so I just want to know what bits to pull off and clean and what should I replace?<br /><br />Thanks a million for your help.

 

[Andrew Brierley]

Re: '94 70HP EVUNRUDE FRUSTRATION!

Pulled the carbies off, stripped them down and found 3 Jets, all were clean but I used carbie clean anyway to ensure the were absolutely clean. Still does not idle smoothly which means when I put her in the water she is going to keep stopping at idle.<br /><br />The other syptom that happened the other day which I neglected to mention was that when I tried to accelerate she coughed and stopped, this only happened twice the rest of the time it was ok. When it did cough the only way to get up to speed was to put in neutral, rev the engine a little and then back into gear and ease the throttle very slowly to build up revs before she would take off. (Now that I have typed that it has hit me that it sounds like a fuel pump problem, if it was a four stroke I would have guessed the accelerator pump)<br /><br />One last thing, is there anyway to adjust idle mixture on these carbies?<br /><br />By now I have realised that no one is reading these posts anymore, but I will continue to log my trials and errors in the hope that someone can benefit from this experience in the future.<br /><br />Regards<br /><br />Modcat

 

[BillP]

Re: '94 70HP EVUNRUDE FRUSTRATION!

Hey, listen to dpminc about the tstat. Your symptoms are exactly what will happen if the engine is running cold. Try the manual choke and see if that helps. Just for kicks you may play with hotter plugs and see if that does any good.