1979 mercury 150 hp throttle issues?

[faithful_unto_death]

Wondered if anyone would help me out with sugguestions on whats going on with my 79' 150 hp mercury cruiser controls. The problem doesn't seem huge and possibly an easy fix. The motor runs fine, when in neutral and pulling the throttle control up it absoluetly roars, runs absoluetly great. Now when its in drive, different story. I had the throttle control all the way up and the drive in full gear and was putting along at a slow 5-10 mph. It seemed like when I kept pulling the throttle up and down it wanted to go faster but it just acted like the throttle wasn't responding to the drive, or when it was in drive well... it was but it shouldn't be getting this reaction. have any sugguestions? feel free to PLEASE HELP!

 

[Faztbullet]

Re: 1979 mercury 150 hp throttle issues?

the motor runs fine, when in neutral and pulling the throttle control up it absoluetly roars, runs absoluetly great.

Take cowling off and without it running put in gear and open throttle all the way and then check your linkage to see if carbs are opening all the way. If so you have a electrical or carb problem as it can run and idle good and rev up on 3 cylinders and have still no power..

 

[faithful_unto_death]

Re: 1979 mercury 150 hp throttle issues?

Take cowling off and without it running put in gear and open throttle all the way and then check your linkage to see if carbs are opening all the way. If so you have a electrical or carb problem as it can run and idle good and rev up on 3 cylinders and have still no power..

I will try this and see what happens. thank you for your help!

 

[mr 88]

Re: 1979 mercury 150 hp throttle issues?

Are you saying it won't accelerate when in gear,if so I would start by opening the 3 idle jet screws one blade width at a time,then test.It will rev up in neutral when the idle screws are not adjusted correctly,but not in gear as the load on the prop changes the dynamics.

 

[faithful_unto_death]

Re: 1979 mercury 150 hp throttle issues?

It's accelerating when its in drive, 5-10 mph but when you pull the throttle up as far as it goes (and i mean ALL the way) it doesnt pick up speed it just remains same. But what doesnt make sense is, when its in neutral and you pull the throttle and gradually climb it, it picks up speed and sounds like its ready to take off.


Before this current problem I had a guy come down and look at the motor/run it before I took it out because Im new to all this and have no idea about boat engines. Anyway, I was pulling the throttle and dropping it just to see how it was running and it sounded pretty steady, he agreed and said it sounded really good, he said he thought it sounded that it was idleing fast and started turning things similiar to what you are describing and said something about it not running fully if they are too tight or too loose, so let me know what you think!

 

[mr 88]

Re: 1979 mercury 150 hp throttle issues?

As I said,neutral and revving it up is not the same as in gear,there is no load on the engine. It will sound like it is idling fast on muffs because it does vs in the water,there is a 2-300 rpm difference in the two. You have 3 carbs and 3 idle jet screws,try opening each one a blade width after you base each one out at 1 1/2 from a light seat. Test after each adjustment,both idling in gear and accelerating.Do to the design of the carbs the transition from slow/idle to fast is dependent on your idle screws allowing a surplus of fuel to feed it at the initial hit when it is in sync with your timing.

 

[Fed]

Re: 1979 mercury 150 hp throttle issues?

You're not trying to drive it with the fast idle lever are you?

Not the first time I've seen people do that.

 

[Faztbullet]

Re: 1979 mercury 150 hp throttle issues?

How about posting the serial number as your getting advice on 2 different motors.. They did not make a 150 Inline in 1979 only a V-6 and it has no carb adjustments other than linkage.

 

[faithful_unto_death]

Re: 1979 mercury 150 hp throttle issues?

Ill try it Mr. 88
Fed, no. the drive is down and im pulling the throttle lever up
Faztbullet, ill get the serial number when I get home but I do know that it is a 6 cylinder. I was unaware there are two

Thanks guys!

 

[Fed]

Re: 1979 mercury 150 hp throttle issues?

Fed, no. the drive is down and im pulling the throttle lever up

Your first post says you're revving with the throttle control in neutral so that has to be the fast idle lever.
Then you say that you put it in gear & try to accelerate with the throttle control.

Unless of course you have a controller with a push button that disengages the shift and allows you to rev in neutral?

The bottom line is that you should be using the same handle for both shifting into gear & accelerating with, if you're doing that the disregard this post.

 

[faithful_unto_death]

Re: 1979 mercury 150 hp throttle issues?

I think this is what im doing. Theres another guy that told me the same thing but I dont understand. I thought by putting the drive down and putting it in gear makes you go and pulling the throttle or fast idle lever makes you go faster.The drive is all the way down and its remaining the same speed, so either i dont know what im doing or i dont know what im doing.

 

[Fed]

Re: 1979 mercury 150 hp throttle issues?

If you push the shifter handle down & the boat doesn't take off then there's probably something wrong inside the controller.
It can't be a broken cable because the fast idle lever does work.

BTW, there is supposed to be a mechanical interlock that stops you putting it into gear unless the fast idle lever is fully down, by memory it should also stop you lifting the fast idle lever whenever it is in gear so I think something must be wrong inside it.

You could try putting it into gear then pushing down further on the shifter to see if the throttle cable is moving at the motor end.

 

[faithful_unto_death]

Re: 1979 mercury 150 hp throttle issues?

ha, Fed you were right all along. I was using the cold/fast idle lever as an accelerator. apparently thats not how it works. totally feel like an idiot but hey, how am i supposed to know if i was never shown? it works just fine, and there was nothing ever wrong with it. i just didnt know what im doing or how to run it correctly. so thank you all for your help, now i know ONE handle drives and accelerates :facepalm:
THANK YOU!!!!!

 

[Jbea29@gmailc.com]

I guess what am I looking for that could be causing this problem. Again thwk

 

[racerone]

Open the low speed mixture needles 1/4 turn and test run.

 

[Jbea29@gmailc.com]

Thank in will do this and get back to you after