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1983 75 HP evinrude

G

Garrett L.

Guest
I took my boat out for the fir

I took my boat out for the first time this year it ran good for about an hour and then lost half the power. I then rebuilt all 3 carbs and adjusted the the needle to what it was it idles fine but when you put it in a foward motion and have a load on it it falls on its face. I have tried to adjust them but not sure which way to go. Planning on rebuilding the fuel pump next but need to know if that might be a problem.
 
"The bulb on the hose is a man

"The bulb on the hose is a manual pump!So if it keeps running using it, it is not the fuel pump."
 
thanks but if the pump is not

thanks but if the pump is not the problem then what else can it be. I was told that it maybe a bad cylinder I have not check the compression yet but might. What kind of numbers should I be looking for when doing one. Also I installed a fuel filter on it would that be the problem. Just wondering if it gets just enough gas to keep running but when putting a load on it there just is not enough flow.
 
"check your spark it may not b

"check your spark it may not be fuel related at all,it will have similar symptoms as to what you are describing.sounds good on flusher but not in water"
 
Do you have compression and sp

Do you have compression and spark on all cylinders? What is the compression? Will the spark jump a 7/16" gap on all cylinders?

Did you manually clean the high speed jets in all of the carburetors?
 
when I took the carb apart I s

when I took the carb apart I sprayed and cleaned everthing. spark plugs are new but might go ahead and get another set to make sure or do you thiing cleaning them and regapping them to 7/16 might do just as well. Have not had a chance to get to the compression test yet kinda weekend mechanic on it but trying to get all the advise I can and try all the things you tell me. Will let you know what I find on compression when I get it done. and hopefully will get it running soon before summer is over. thanks to all of you.
 
"you'll never gap them at

"you'll never gap them at 7/16"---
the factory setting,for that eng is .030 on a ql77jc4 plug"
 
sorry about that miss understo

sorry about that miss understood what you wrote. What is the proper gap on the plugs.
 
Joe you were asking if I clean

Joe you were asking if I cleaned the high speed jets on my carbs. Well I went back over my parts manual looking for the part you are talking about and I see no discription of a high speed jet. if you can tell me where to find what you are saying a high speed jet is then I can know for sure if I cleaned it or if it is something I need to take care of. Thanks
 
"your jets,are brass,and they

"your jets,are brass,and they are in the bottom of the carb bowls,..pull the bowl off,pull the drain bolt,and u can look in and see it.."
 
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Just registered so my user nam

Just registered so my user name has changed. jwb I know what you are talking about I tryed getting them out but the were in so tight I was scared I might damage them trying to get them out. So I soaked that part of the carb in carb cleaner for about an hour. Maybe you have an idea how to get them out with out damaging them since they are so tight.
 
"sometimes i remove them,most

"sometimes i remove them,most of the time ,not,...due to exactly what u r talking about...just make sure thay are chrystal clear,...use a flashlite to verify,..."
 
ok will do just that. And than

ok will do just that. And thanks again will keep you informed about the rest when I get to it and hopefully with your help I will not only get my boat back on the water to have fun but gain some knowlege as well.
 
ok checked compression had 140

ok checked compression had 140 in #1 145 in #2 and 140 on #3 spark plugs jump over 7/16 of an inch. cleaned jets till they shine and still have the same problem of it falling on its face when you put a load on it. So what next do I need to check.
 
also need to add that this is

also need to add that this is the first year I ahve had an in-line filter on it can that be a problem even though it runs fine with no load on it? Also when I put my hand over each of the air intakes number 1 and 2 carbs the enine almost died which I can understand but number 3 did nothing but you can feel some vacumm pull on it. Does this mean the carb is bad or do you think I might have more problems than i can deal with?
 
Mr. Reeves or jwb when you get

Mr. Reeves or jwb when you get a chance can you take a look at what I have writen and see what kind of ideas you might have on what my problem is. Or do you think it maybe something to let a professional deal with
 
"Either a problem exists with

"Either a problem exists with number three carburetor OR a problem exists with the related reed plate (leaf valve).

This is assuming that you are correct that you do have the compression indicated above AND that, with the spark plugs removed, the spark jumps a 7/16" gap constantly on all cylinders at cranking speed.

A sticking timer base under the flywheel will also cause the engine to fall on its face when throttle is applied BUT that would not affect that #3 carburetor."
 
yes I do have the compression

yes I do have the compression and yes it jumps a big gap. I do know that before I bought the boat that they replaced the number 3 carb. So maybe I just another bad one. can the reed valve be replaced and what would I be looking for on the diagram. just tell me the number and i will see. How would someone check the timer or should I leave that up to the professionals.
 
"With the carburetor face plat

"With the carburetor face plate removed and the engine running with the condition you speak of existing, stick two fingers into that bottom (#3) carburetor throat. If the rpms pick up and the engine smooths out somewhat, something is clogged in that carburetor.

Timer Base: Engine not running. Spin the prop so that you can shift the engine into forward gear. Have someone slowly move the throttle from idle to full throttle while you observe the timer base under the flywheel.

It should move smoothly from its idle xlocation clear up to its full spark advance position, that is right up against the rubber stop cap that is attached to the full spark advance screw.

If it sticks anywhere, find out why and correct it."
 
OK Joe stuck fingers in carb a

OK Joe stuck fingers in carb and nothing changed. also checked the motion of the timer base and it was working smoothly. The only thing I can come up with is that even though I rebuilt the carb it may just be bad do you know of anyone that has a good one they might sell the carb number is 394812 mx75. I went to my local dealer and they are telling me that it is a ventage style so it might be hard to come by.
 
what is the correct ratio mixe

what is the correct ratio mixer for this 75 hp motor. Also does anyone have any ideas on how to find the leak I am having on the carb. it seems to be sucking in air somewhere else besides the front so I can decided whether or not it can be fixed or junked. And does anyone have a service manual they might be willing to share so I can work on this thing correctly. I want to thank everyone who has helped me in the past and hopefully in the future. Also would like to get a hold of the parts catalog with the discription and part numbers.
 
"Mixture is 50/1.

To repeat


"Mixture is 50/1.

To repeat myself, if you indeed have the proper compression and spark on all cylinders, ihncluding that bottom cylinder (#3), I'm still at the bottom carburetor or the reed plate. To inspect the reed plate properly, it would be necessary to remove the intake manifold.

Is fuel actually entering that bottom carburetor. Remove the drain plug on the bottom front portion of the float chamber for confirmation. When you stuck two fingers into that carburetor throat, you should have felt fuel being drawn up thru the high speed venturi.

I've reread everything here but see no mention of the model number of that engine. What is it? The 1983 70/75hp models do not have any adjustable needle valves and your mention of adjusting a needle makes me wonder exactly what engine that might be.

It escapes me which cylinder operates the fuel pump on that engine. Check to see if the pressure line/fitting/surface might be faulty.

Should those carburetors have adjustable needle valves at the top front portion of the uppper body, adjust as follows.

(Carburetor Adjustment - Single S/S Adjustable Needle Valve)
(J. Reeves)

Initial setting is: Slow speed = seat gently, then open 1-1/2 turns.

Start engine and set the rpms to where it just stays running. In segments of 1/8 turns, start to turn the S/S needle valve in. Wait a few seconds for the engine to respond. As you turn the valve in, the rpms will increase. Lower the rpms again to where the engine will just stay running.

Eventually you'll hit the point where the engine wants to die out or it will spit back (sounds like a mild backfire). At that point, back out the valve 1/4 turn. Within that 1/4 turn, you'll find the smoothest slow speed setting.

Note 1: As a final double check setting of the slow speed valve(s), if the engine has more than one carburetor, do not attempt to gradually adjust all of the valves/carburetors at the same time. Do one at a time until you hit the above response (die out or spit back), then go on to the next valve/carburetor. It may be necessary to back out "all" of the slow speed adjustable needle valves 1/8 turn before doing this final adjustment due to the fact that one of the valves might be initially set ever so slightly lean.

Note 2: If the engine should be a three (3) cylinder engine with three (3) carburetors, start the adjustment sequence with the center carburetor.

When you have finished the above adjustment, you will have no reason to move them again unless the carburetor fouls/gums up from sitting, in which case you would be required to remove, clean, and rebuild the carburetor anyway.

When time permits, visit my eBay store at: http://stores.ebay.com/Evinrude-Johnson-Outboard-Parts-etc?refid=store"
 
sorry about that joe the motor

sorry about that joe the motor is E75TRLCTE. Yes I did comfirm that there was fuel in the bowl. I also went as far as taking the number 2 carb and putting it down to the number 3 spot and put number 3 to number 2 cylinder and the same thing happened when you put your hand over the air intake of each the number 3 cylinder with the number 2 carb killed the motor and when you covered the the number 2 cylinder with the number 3 carb the engine kept running like a champ. Makes me think that that carb might have a fracture somewhere in the casting but not sure.
 
"Well I have read the entire p

"Well I have read the entire post of events and from my technical troubleshooting background of electronics maintenance, if you swapped the #2, and #3 carbs like you said and the problem you described moved from the #3 to the #2 when you swapped the carbs then logic says the problem is with the component you moved. If #3 before the move didnt kill the motor when you covered the air intake for it and you moved it to #2 and it does the same thing then that carb has some sort of issue. Especially if the #2 carb now in the #3 slot kills the motor now when you cover the air intake for it. Just my logicical thought process."
 
Well thats my thought as well.

Well thats my thought as well. However instead of just junking the carb maybe it might be just a simple fix but what I need to find out is how does one find the hole in which it is sucking air. Or can it be something else that might be the problem. The fact is I dont have $150 to spind on a new carb. So if i can jb weld the sucker and make it work until I get the money then I will do it.
 
Did you say you rebuilt the ca

Did you say you rebuilt the carbs? If so make sure everything was put back together right and you did not crimp a gasket or forget one or something. If not I am not sure how you could find the leak in it without some type of leak detector.
 
"Yep..... The carburetor is th

"Yep..... The carburetor is the problem. When this is solved, if you replace that carb, I'd like to see it. I'd ship it back to you of course."
 
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