Heeeelp Evinrude 140 again - paging 2KBoat or Evinrude aces

[Pannet]

Re: Heeeelp Evinrude 140 again - paging 2KBoat or Evinrude aces

Dear NGRIFF1,<br /><br />My Evinrude V4 140hp 1990 used to have a problem of intermittent power loss and die at idle. I cleaned the carb, not improved. I changed the fuel pump using a non-VRO type and used premix gas, idle great, power loss problem improved but not disappeared. I changed the fuel filter to a larger one ( a higher flow ), the power loss problem was almost disappeared ( only occasionally at WOT ). I then rechecked the carburetor and found that one of the float was set too low, I adjusted the float and the problem had gone. I also found that the carburetor's gaskets were hard and stiff with some gas leak so I changed all. My motor runs great now.<br /><br />I think our motors are old now and many parts are nearly come to an end of their lifes and may help contribute to the same symptom. As in my case, if the fuel pump is strong, minor improper adjustment of the float together with a partially clogged fuel filter may not cause any symptom.<br /><br />Running the motor with carb cover off make it run lean. Most of motor will not run good or reach WOT with that cover off. If your motor run better with carb cover off, may be one or two carbs are running too rich or flooded when carb cover is on. May be due to the high setting of the float or defective needle / seat. Also check for the fuel hoses inside the carb cover they may be kinked or pinched by the cover.<br /><br />I'm a doctor not an expert. Just trying to help diagnose your problem.<br /><br />Good luck.

 

[Neil]

Re: Heeeelp Evinrude 140 again - paging 2KBoat or Evinrude aces

Thanks for the input on this.<br /><br />Fuel filter is not something I have checked, but it is clean and used to work OK. <br /><br />With the cleaning of carbs and air cover off it could be carb related.<br /><br />In one of the 1st posts Dhadley suggested running with the air cover off and then changed his mind with a firm DO NOT RUN WITH COVER OFF.<br /><br />Is there a reason for this apart from obvious risk of water digestion. THe OMC ran it for quite some time with the cover off.<br /><br />NG

 

[Pannet]

Re: Heeeelp Evinrude 140 again - paging 2KBoat or Evinrude aces

Dear NGRIFF1,<br /><br />I once ran my motor with the carb cover off ( which I learned later that I should not ) to check for fuel leak from hoses / carbs after I had rebuilt them. I learned that with carb cover off, my motor could't rev beyond approx. 3,500 rpm. It would bog down and die at WOT. After I put the carb cover to it's place, the motor ran normally. The water ingestion resulting from running while carb cover is off may not happen easily.

 

[Walker]

Re: Heeeelp Evinrude 140 again - paging 2KBoat or Evinrude aces

Seems like you have checked most everything. I believe you coils are grounded thru straps on one mounting screw per coil. Try cleaning the straps and the block where they make contact. Put a dab of dielectric grease on each one too. <br />Also, one more question, is your gas fresh??

 

[Dhadley]

Re: Heeeelp Evinrude 140 again - paging 2KBoat or Evinrude aces

To answer your question about the air box, without it on a looper your motor will run leaner. As much as 12 to 15 numbers (jet size) on some. I've seen a piston stick from that alone on a test run. The sad part was the guy did it twice.<br /><br />What I said was if you have the air box off to verify throttle plate positioning or check for a pinched hose, do not run it at speed with the air box off. <br /><br />The clue lies with your post about the box. When the mechanics cleaned the carbs did they switch the high and mid range jets by mistake? Did they rejet for some reason?<br /><br />Start with the basics!

 

[ob]

Re: Heeeelp Evinrude 140 again - paging 2KBoat or Evinrude aces

Sounds like carb sync problem.Perhaps opening too early .However without looking don't know if they're sincronized with each other.There should be a factory scribe on the carb linkage cam that should align with center of linkage roller.This determines at what point your carbs begin to open in relation to ignition .This setting is very critical when throttling up from idle in gear position .However if you say it checked out good after final dealer service finding restriction in carb then you probably have some reocurring restriction.Fuel tank ,hoses ,fuel pump,and anything else in system before carbs needs to be inspected closely for contaminates until they can positively be ruled out.

 

[Neil]

Re: Heeeelp Evinrude 140 again - paging 2KBoat or Evinrude aces

Ignition coils have been replaced as well as the entire ignition control box.<br /><br />When I first received the engine back from rebuild and discovered poor performance OMC mech took boat back to their workshop. They said the rejetted to take account of the rebore (1 cylinder). When they ran engine in tank with test prop they could see no problem and engine revved high.<br /><br />After all electrics replacement they removed carbs and returned saying they cleaned. We ran at sea with no problem. Lots of power, no missfire and lots of torgue at all throttle range. Returned to shore, replaced cover, ran engine and shut down.<br /><br />Next day I take boat out, exactly same symptoms.<br /><br />I had 4 different fuel sources. I started with the original from the previous day, then moved to 2 different tanks (one with a 25:1 ratio) and even inboard which has a different fuel system. No change so I can rule out fuel supply. If my fuel filter was causing a restriction I would have encountered this earlier.<br /><br />OMC mecs return again tomorrow and I will pay close attention to the carb settings. I will fit a skuttle valve this evening just in case I throw in the towel.<br /><br />Thanks for staying with this.<br /><br />NG

 

[Brew]

Re: Heeeelp Evinrude 140 again - paging 2KBoat or Evinrude aces

Check the high speed jets again on the carbs. If that was the problem the first time and it ran great after cleaning them, maybe something has clogged them again.<br /><br />My Evinrude '86 140 has been giving me grief all summer. I cleaned the jets at the beginning of summer and therefore assumed that couldn't be my problem. Last weekend I discovered that a small piece of plastic had clogged one of my jets since the first time I cleaned them.<br /><br />If something foreign was introduced to the fuel system during the rebuild, maybe pieces of it keep working there way into the high speed jets.<br /><br />Check the simple stuff first.<br /><br />Good Luck!!

 

[Neil]

Re: Heeeelp Evinrude 140 again - paging 2KBoat or Evinrude aces

I have been reading a lot of posts relating to carbs.<br /><br />I will certainly focus on this.<br /><br />Thanks.<br /><br />NG

 

[Dhadley]

Re: Heeeelp Evinrude 140 again - paging 2KBoat or Evinrude aces

Start with the basics!!!<br /><br />You say they have re-jetted the carbs. Lets go back to stock jetting!!!<br /><br />If they drilled the jets, have them replaced with the CORRECT STOCK jets. No drilling!<br /><br />If you have a reoccuring trash problem, then the air box cover on and off deal may just be coincidence. <br /><br />Make sure they have the low and mid range jets in the correct place.<br /><br />Good luck!

 

[mrc]

Re: Heeeelp Evinrude 140 again - paging 2KBoat or Evinrude aces

Agree with dhadley, Since original problem was crud in the jet, and presumably<br />they had rebuilt the carbs with the powerhead rebuild (it's cheap, and good <br />insurance). Something might be shedding crud into the fuel supply of the carbs.<br />Something between the fuel filter and the carbs. And the engine ran well for<br />awhile before problem reoccured.<br /><br />Replace the fuel lines feeding the carbs from the fuel pump.<br /><br />If possible (and cheap) replace the fuel pump. If not possible, take a good<br />long hard inspection of the fuel pump.

 

[Walker]

Re: Heeeelp Evinrude 140 again - paging 2KBoat or Evinrude aces

Have you tried running the boat with the engine cowling off. If you have an exhaust leak at the base gasket, or anywhere else for that matter, it could fill up the airspace under the cowling with exhaust gasses.

 

[Neil]

Re: Heeeelp Evinrude 140 again - paging 2KBoat or Evinrude aces

Getting closer.<br /><br />I suggested to the OMC mecs that they check again with the air cover off as it ran fine without it.<br /><br />They seem to be working in line with Dhadleys thoughts.<br /><br />They took the catb cover off and had much discussion. I couldn't keep up with this as they are Indian. There was a lot of fuel inside the cover but I don't know if this should be so or not. Anyone advise on that?<br /><br />Anyway, they seemed to agree that the engine was getting restricted air.<br /><br />They replaced the fast speed air jets for bigger ones( can some one also confirm there are such a thing) and we took the boat out. From idle to high speed the boat took off ok. When I went from idle and slowly increased throttle speed, engine just stalled.<br /><br />Idle to WOT seems to be OK.<br /><br />Mechanics say they will need to come back to replace my mid range jets and this should cure the problem.<br /><br />There is no fuel blockage. All my filters are clean.<br /><br />What is simply don't understand is why I had this problem in the fist place. Engine ran fine before rebuild. Only one piston was rebored, the rest just had new rings. <br /><br />So, the saga continues for a while but hopefully drawing to a close...<br /><br />NG

 

[Dhadley]

Re: Heeeelp Evinrude 140 again - paging 2KBoat or Evinrude aces

I am assuming that you meant the idle air jet, not high speed air jet (the high speed jet meters fuel). That makes sense. The idle and mid jets are air jets, so if they went bigger they are introducing more air. I still bet they reversed the jets when they cleaned the carbs.<br /><br />Again -- be very careful running at wot with the airbox cover off. In fact, don't!

 

[seahorse5]

Re: Heeeelp Evinrude 140 again - paging 2KBoat or Evinrude aces

To do a quick check to see if it is a mid-range jet problem, use round toothpicks, broken in half, inserted into each mid-range jet. Those are the upper of the 2 airjets on the front of the carbs. Blocking off the air jet richens the mid-range. Run the motor briefly to see if it accelerates the way you want it to. It may "blubber" or run rough in the 1200-2000 rpm range because of more fuel being delivered.<br /><br />If this does not help acceleration, then you may have restricted internal passageways inside the carbs, most common are plugged brass pick-up tubes.

 

[Neil]

Re: Heeeelp Evinrude 140 again - paging 2KBoat or Evinrude aces

Dhadley,<br /><br />You are most certainly correct with your terminology, I am just repeating what I was told.<br /><br />The guys are working on the engine now so I will go and see what they are up to.<br /><br />I have been reading lots of articles on carbs and the adjustment appears to be critical. When I watch these guys tune my boat and others at the marina here they do the carb adjustment by trail and error and mostly by ear. There must be some more science to it than that. When I tune a car engine I either use a colour tune to ensure it is not lean or use a CO ananyser. What is the best way to tune an engine with 4 carbs like mine. As soon as these guys have finished and convince me that the rebuild is OK, I wish to finely tune the engine. I have no manual and I am struggling to get one delivered here. I am hoping that Elisport Marine can now save the day as they have one. Should this provide all the information I need?<br /><br />Carbs have been completely stripped and cleaned so I don't expect a blockage.

 

[Pannet]

Re: Heeeelp Evinrude 140 again - paging 2KBoat or Evinrude aces

Dear NGRIFF1,<br /><br />If your carburetors are MINLON type carburetor as mine, the carburetor's body is made of black plastic. They are attached to the metal throttle body and can be removed for service individually. On mine carburetors, there are no screw for fuel mixing adjustment. The idle and intermediate fuel mixture are controlled by fixed idle and intermediate air bleed orifices. The high speed fuel mixture is controlled by a fixed high speed fuel orifice. They are all set, no adjustment. I think you should not change the size of any orifices since you told that the motor ran OK before the rebuilt.<br />If the fuel and air passages are not blocked / not leak, the motor should run OK. Rubber gasket for the side window of the idle and intermediate air-fuel passage, if leak, can cause error in idle and off idle too. <br />Did they change the Carburetor's gaskets, o-ring seal, needle valve and seat during the carb rebuilt ? Mine motor has some oil inside the carb cover not the fuel. You may have fuel leakage somewhere or a problem with float / needle.

 

[MGuckin]

Re: Heeeelp Evinrude 140 again - paging 2KBoat or Evinrude aces

Float level, idle stop, link/snyc, base timing, timing advance stop are the only adjustments.<br />No mixture screws such as in an automotive application.<br />I read an article somewhere about this. At 1 time there were screws but with multiple carbs, it was almost impossible to get them to work together.<br />Motor should be running all stock "fixed" jetting.<br />Only reason for increase on a stock motor is altitude adjustments and what you had worked before.<br />Boring 1 jug should not require rejet.<br />Long shot and probably not this simple but, when the air box was reinstalled could you possibly have kinked a hose somewhere?

 

[Neil]

Re: Heeeelp Evinrude 140 again - paging 2KBoat or Evinrude aces

I don't know the colour. I think they are black but guessing at this point.<br /><br />I lust got a call from the mechs. They changed the intermediate jets on the carb and it now performs as it should at all throttle points.<br /><br />I will need to get a written report as to just what jets have been replaced and at which point.<br /><br />Hopefully I will be a happy boy again. <br /><br />If it is performing OK, how do I ensure it is not running too lean? If there are no carb adjustments I presume it is automatic?? I hear stories of pistons holing because of a lean mixture but the engine was running ok priopr to this. As it was a piston that caused all this I wish to have fine tuned engine.<br /><br />Thanks for the help so far.<br /><br />NG

 

[iRich]

Re: Heeeelp Evinrude 140 again - paging 2KBoat or Evinrude aces

it sounds to me like you should get a different mechanic to take a look at it. to be a good mechanic you need to be a good troubleshooter.<br /><br />Rich