I have to choke it to throttle?

[oxbeast1210]

TE150SLCEM 1989 evinrude xp tracker 150hp

Hello everyone im back.
i'm having on issue on the boat where if i try to speed up the
motor shuts down at about half throttle if i keep it below half throttle its fine i can stay there all day but as soon as i try to go further it dies.
here is the catch if i try to throttle past half way and coke it at the key switch
it advances fine and speeds up and runs great, that is until i slow down below half throttle then i get the same issue where i have to choke it at the key so it doesn't die past half throttle can anyone please give me some things to check ?
or what could possibly be causing my issues
thank you

 

[F_R]

Re: I have to choke it to throttle?

I'm not familiar with your model, but the problem is common on many others when the timer base is sticky. That causes it to lag behind the carburetors' throttle opening.

 

[Haffiman]

Re: I have to choke it to throttle?

You either have a problem with the intermediate circuit in your carbs, or an air-leakage in the high speed circuit.
Pull the carbs, REMOVE all jets and clean out passages, replace ALL gaskets.
When re-installing, double check the link ans synch.
The main circuit needs a certain air speed in the carbs to start working. If RPM is to low (too heavy prop) this may also happen.

 

[tashasdaddy]

Re: I have to choke it to throttle?

pushing the key in to "choke" it, is a sign of fuel restriction. as said intermediate jets. pushing the key in, activates the primer, which squirts fuel/oil directly into the intake manifold, by passing the carbs.

 

[oxbeast1210]

Re: I have to choke it to throttle?

Ok thank you
is it normal for it to run normal after the initial choke? I only press it once and it will continue to run good until i get back to almost idle the if i try to go again i have to press the choke again and its fine.
does it continue to bypass the carbs once its pressed once??
thank you

 

[Haffiman]

Re: I have to choke it to throttle?

It only squirts fuel when pressed/activated.
What probably happens is that you get up the revs and airs peed in the carb throats enough to get the main jets started.

 

[oxbeast1210]

Re: I have to choke it to throttle?

Ok i understand now thanks
Is this a DIY job or do you recommend i seek
help from a local mechanic?
thanks

 

[F_R]

Re: I have to choke it to throttle?

I'm not saying you don't have a carburetor problem, but I am saying that you have three carburetors, each with two barrels. In effect, that is six carburetors. So, all six have a restriction in the intermediate jets? Or even two or three of them?

As already suggested, airflow speed through the carburetors is the key here. And as I said at the beginning, if the spark timing lags behind the carburetor throttles, they open before RPM goes up, and airflow speed falls on its face. At least check the timer base for stickyness and/or link&sync before tearing into the carbs. It only makes good sense to check the easy stuff first.

If it actually is a carburetor problem, who knows?---Somebody may have even put the wrong jets in it. Stranger things have happened.

 

[tashasdaddy]

Re: I have to choke it to throttle?

as a matter of fact, there is a thread on here that the jets were put in the wrong fittings.

 

[oxbeast1210]

Re: I have to choke it to throttle?

F R ,
thank you for the advice your right it makes sense to check the easy stuff
first before running out and spending money on something which may not be the
issue .So ill follow your advice .Sorry for my lack of knowledge but what exactly do you mean by checking the timer base for stickiness and link and sync is covered in my manual but in words i can understand what does that mean?
thank you!

 

[F_R]

Re: I have to choke it to throttle?

OK, the basics are: At slow idle, all of the carburetor throttle pates are supposed to be shut tight, and the RPM is controlled by spark advance/retard. As you move the control to increase speed, the spark starts to advance and at a certain point a cam starts to open the carburetors---that is the "sync" part, and should be covered in your manual.

As you continue to move the control, the spark continues to advance and the carburetors are slowly opened by the cam.

Once the spark is fully advanced, the carburetors are only open about 1/4 way. From this point onward, further control movement opens the carbs all the way without any more movement of the spark/timer base.

So....The linkage between the throttle control and timer base is driven by a coiled spring. If the timer base sticks and doesn't want to move as it should, the timer base is standing still while the spring winds up and the cam opens the carbs. And it falls on its face.

EDIT: To demonstrate what I'm talking about concerning the spring, put the control at about 1/4 throttle (not running). Now use your fingers to move the upper end of the timer base pivot arm back and forth. Notice that it is moved by spring force, not a solid mechanical connection. It must move easy enough for the spring to do the job.

I don't know if that is the problem here or not. But it certainly warrants an inspection.

 

[oxbeast1210]

Re: I have to choke it to throttle?

Hello so i checked what you said the main thing i noticed was that there is alot of some kind of dark Grey residue around the spring area the pictures of what i am talking about are attached is this what you are talking about ? and if not could it still be the cause of my problem??
thank you so much!

 

[oxbeast1210]

Re: I have to choke it to throttle?

My other question is about this little lever that attaches to the timing base should it be able to move freely with the ball joint or should i push the joint in all the way so it doesn't move at all?
thank you
photos attached

 

[F_R]

Re: I have to choke it to throttle?

The link looks ok from what I can see. And the other is probably just lubricating grease. I borrowed your picture to show what should move when you move the control toward fast.

 

[oxbeast1210]

Re: I have to choke it to throttle?

F R ,
thank your for your detailed and helpful responses !
i have another question can you look at these pictures and tell me if there is an issue or not . both were taken with the throttle all the way forward should the cam be pushing the roller forward more like in the pictures where im pushing the roller with my finger? I tried adjusting the throttle cable but its already as far out as it can go
thanks

 

[F_R]

Re: I have to choke it to throttle?

You'll have to get the book out and see how it is sync'd.

 

[oxbeast1210]

Re: I have to choke it to throttle?

Hey everyone just wonted to give an update to my issue so others can learn from my journy lol.
anyway the mechanic called me today after looking everything over .he said the compresion is great and overall the motor is in good shape for its age so that made me feel better. here is the list of things that need to get done. he checked out the whole motor ill start with the ones he said where more likely causing my original issue.:

fuel pump pressure is very low
1 carb needed a rebuild ( hes doing all three anyway)

other issues :
timing off by 5 degrees
coil number 5 is bad
lower unit seal leaking gearcase oil
trigger is weak?

anyway just wated to post this so others can learn from it
i will update again once everything is done