update:desperate help for 140 v4 omc

[HighTrim]

Re: major help needed desperately on evinrude motor

Re: major help needed desperately on evinrude motor

If the information you are providing is correct, I wouldnt use that mechanic anymore. This surely does sound like an air leak into the crankcase, but dont go ripping apart the motor until you do some more investigating as advised. I would take FR up on his offer and talk to him. You may very well need some adjustments, including the throttle cam. Im not 100 percent, and others will be able to verify for me, but does your throttle cam have "START " marked on it? If so, when the warm up lever on your control box is moved to the START position, the START mark on the throttle cam should center on the cam roller. If it does not, turn the stop screw in the control box in or out to obtain proper adjustment. I say this because this needs to be done when the engine idle speed is changed enough to require throttle cable trunnion adjustment, and it sounds like you have been playing with the idle speed screw. You will then need to do a link n sync. This is to ensure proper spark advance at all throttle settings. Open the throttle to wide open and adjust WOT stop screw so that throttle valves are full open without strain on throttle shafts. Then connect a timing light to #1 cylinder. Start motor and advance warm up lever to show 5 deg advance timing. Stop motor and adjust throttle cam yoke to align embossed mark on throttle cam with the center of the throttle cam roller. Open throttle to WOT. Adjust full throttle adjustment screw to prevent strain on throttle shaft. A thin strip of paper between the roll pin and stop should pull out with just a slight drag. With timing light still connected, start motor and check timing as per your manual. Adjust the idle adjustment screw so the motor will idle at 650 max rpm in gear and under load, or about 1000 of the muffs like Joe said. If the timing pointer has been disturbed, you should also check it as per your manual. Joe Reeves will be able to guide you with checking your timing, he has a good guide for it.

 

[Joe Reeves]

Re: major help needed desperately on evinrude motor

Re: major help needed desperately on evinrude motor

It's unlikely that the mechanic meant there would be a clearance between the piston rings and the cylinder walls. I would assume he was speaking of the ring gap that must exist between the ends of the rings when compressed within the cylinder which is between a minimum gap of .007 with the maximum gap being .017.

No offense intended to anyone here but personally I have never performed a leakdown test. The compression test was most important to me, and if faulty, the engine was torn down completely to correct that problem.

 

[sailormanbigd]

Re: major help needed desperately on evinrude motor

Re: major help needed desperately on evinrude motor

update: yes motor does have a "start" marked on the throttle arm thing with two adjacent lines. I fired it up-after charging two new batteries and ran it. The idle was eratic, fluctuating from 900-1100 rpm. I sprayed carb cleaner around at different gaskets and found that if i sprayed the lower part of the intake gasket it would slow down and stall. It did this on both sides of the engine. Also, i sprits alittle in the carb throats-the upper would cause immediate drop in rpm, but i could give a much more stronger spray into the lower carb and hardly had any effect? Does this mean that the lower intake manifold gasket is loose/leaking? or just coincidence? thanks all for all the advice. Patrick

 

[sailormanbigd]

update:desperate help for 140 v4 omc

hi yall, i just started the motor, after charging my new batteries from sitting for 6 months. I sprayed gumout around the gaskets and found what i feel is a leak. When i sprayed the botoom of both sides of the intake manifold gasket it would drop rpm;s and stall the motor. Also, if i when i would put just alittle sprits in the upper carb throat it would stall immediately. But i could spray alot more in the lower carb and it wouldn;t hardly change rpms. Is this from leaking air at the intake base gasket?
Where is a reliable, honest, and reasonable parts source for my old omc. 1979 140hp 20"shaft with pt&t. thanks everyone. Patrick

Ps. I will be very upset if after they had my boat for 6 months it turns out to be a simple gasket-intake. Patrick

 

[R.Johnson]

Re: update:desperate help for 140 v4 omc

You most certainly have a leak. Start with a compression test before you start taking thing's apart. Spraying into lower carb's without a change could be same problem, or something else. A compression test will save both time, and money.

 

[tashasdaddy]

Re: update:desperate help for 140 v4 omc

agreed

 

[sailormanbigd]

Re: update:desperate help for 140 v4 omc

if you read other posts, compression check was already done and the motor tested out fine-according to mechanic. thanks, i think i am going to replace the intake manifold gasket and maybe the reeds. Now where i can get them?
Patrick

 

[Joe Reeves]

Re: update:desperate help for 140 v4 omc

As a suggestion.......

Some years back, there was a 150hp manufactured that was prone to intake manifold leakage. The cure as per a OMC service bulletin was to double gasket that manifold. Doing so cured the problem.

If your present gasket looks normal, it might be a good iddea to double up on that one.

 

[Ranger 330V]

Re: update:desperate help for 140 v4 omc

saliorman, I just read your thread and hope things get better..I just got my 78 140 going on the water yesterday and it is such an awsome engine...I need alot more prop as I hit 6300 rpm ( for a sec to verify) at 43mph with a 13 1/4 X 17 prop...can't wait to get a 19 or 21. Anyways...just a tidbit of info about spraying the carb cleaner...be careful with that...get some deepcreep by sea foam or something like that to spray in there...carb cleaner does what it says...it cleans and as you spray into the carbs it "cleans" the pistons and cylinders of oil (leans it out)...just a tidbit I picked up from the guys here...be careful with that stuff. Good luck and keep us updated!