1992 70hp Force motor cam shaft just a hair forward to much, causing high idle

[privfisher]

Hello this is my first time asking a question here, but I have read alot of info/forums on here and its been great responses.
I am having a problem with my 70hp/3cylinder/Single carb Force motor, seems to be a mild adjustment problem. Do not want to take to mechanic and pay huge amounts of $$$$ for something that seems to be simple fix.
Anyway the problem I am having is when shift lever is in idle position, the throttle cam is being pushed forward just enough to keep idle high, cam not lining up with center mark to roller. It needs to come back about 1/8'' or less to close carb completly for normal idle. So do to this problem the idle stays way to high. I can pull cam back off the carb roller with throttle arm disconected and it will idle fine. I have tryed adjusting the little double loop ended throttle arm to cam linkage and shorten shorten it a little, but did not help, because it wont open throttle all the way to hoizontal position when in WOT. As far as shifting cable it seems fine, shifts nicely into forward and reverse so smooth and easy when in normal idle.
So what I'm asking is, could it possibly be the idle adjustment screw? (Not sure where idle adjusment screw is even after reading tons of threads.) Throttle cable adjustment? Or is it something on the tower that needs adjusted. Its so close to running perfect, but I dont wanna screw anything up. So any help, advice would be much appreciated. I would love to go boating this Labor Day weekend, but without throttle, not possible, unless I tie a string to the throttle cam....

 

[Jiggz]

Re: 1992 70hp Force motor cam shaft just a hair forward to much, causing high idle

It's probably and most likely the idle screw adjustment. Search for TwoFish posts which shows a good picture of the idle screw. But if you want to find it out yourself, it is at the bottom of the timing tower with a screw and a lock nut on it. The locknut is a 7/16" nut and the screw is a 1/4-20" screw. Turning the idle screw CW will increase idle rpm while CCW will decrease it.

 

[privfisher]

Re: 1992 70hp Force motor cam shaft just a hair forward to much, causing high idle

It's probably and most likely the idle screw adjustment. Search for TwoFish posts which shows a good picture of the idle screw. But if you want to find it out yourself, it is at the bottom of the timing tower with a screw and a lock nut on it. The locknut is a 7/16" nut and the screw is a 1/4-20" screw. Turning the idle screw CW will increase idle rpm while CCW will decrease it.

Thank you for the info, am gonna go look for this screw and locknut now. Wil this help pull the throttle cam back just off the roller?

 

[privfisher]

Re: 1992 70hp Force motor cam shaft just a hair forward to much, causing high idle

Jiggz, the only screw/nut I can find on the tower arm shaft is the stop screw that hits the block. Is the idle adjustment screw above or below the stop screw? I see the spark adjust screw at the top under the flywheel, but I dont think I wanna mess with that.
I looked at TwoFish posts, but couldnt find any pics of that area that I am looking in.
Thanks for your quick response on my earlier post.

 

[privfisher]

Re: 1992 70hp Force motor cam shaft just a hair forward to much, causing high idle

Jiggz, the only screw/nut I can find on the tower arm shaft is the stop screw that hits the block. Is the idle adjustment screw above or below the stop screw? I see the spark adjust screw at the top under the flywheel, but I dont think I wanna mess with that.
I looked at TwoFish posts, but couldnt find any pics of that area that I am looking in.
Thanks for your quick response on my earlier post.

I did find a picture listed by TwoFish, it was for a 2carb, but I saw the red arrow pointing to the idle adjustment screw on the tower arm. So what I know the stop screw as, is actually the idle adjustment hhmm, so will try adjustment, put in water, then try to sync up air/gas mixture, hope that gets me going for the weekend. Thanks for the info Jiggz, much appreciated

 

[jerryjerry05]

Re: 1992 70hp Force motor cam shaft just a hair forward to much, causing high idle

The gas air mix should be about 1 turn out.
Set it there for inital adjustment.
Then adjust it after it's warm.
In till it chokes/coughs/stalls.
Then out 1/2 turn.

 

[privfisher]

Re: 1992 70hp Force motor cam shaft just a hair forward to much, causing high idle

Thank you Jerry for letting me know. Maybe you have some tips for me on the above topic. I adjusted the idle screw ccw and cw. Did not make a difference. I adjusted the little throttle link with the 2 loop looking ends. Not sure where to set it back to know OOPS!
When i adjust the throttle links out to where I think, or where they were set at, and push forward on the control lever, then pull back to nuetral the throttle cam comes right back to resting on the roller. Still putting enough force to keep carbs open maybe an 1/8'' or so. Which causes way to high idle. I have to kill the motor immediately. I can pull the throttle tower arm back and it will pull the throttle cam off the roller, and they line up fine. Could this all be due to slop in my throttle cable? Thank you for any info in advance, very much appreciated.

 

[Frank Acampora]

Re: 1992 70hp Force motor cam shaft just a hair forward to much, causing high idle

It is actually called the idle stop screw. Yes, it does adjust the idle speed. NO, the cam should not be off the carb roller or even just touching it. The carb should NOT be completely closed at idle, nor should the line on the cam be even with the roller.

Typically, to initially set the carb, the cam IS set with the line just touching the roller. The roller is on a cam screw and turning the screw adjusts the roller in or out. Once this is set, then the cam is set by the ball link to open the carb all the way at wide open throttle. Timing is set to factory specs at wide open throttle, THEN, the idle speed is adjusted with the idle stop screw.

Assuming that the timing is correct, simply back out the idle stop screw until the engine idles at 700-750 RPM in forward gear, in the water.

If you can pull back the throttle by hand, then there is a cable or linkage problem. IF you have Mercury controls, the throttle cable MUST be adjusted after changing idle speed or ---the throttle may not return to the idle position. Sound familiar? SO: If your throttle and timing are not returning fully to idle position, assume that the previous owner has not correctly adjusted cables. Remove the throttle cable from the clamp and screw the brass plug in or out -- I forget which way-- until the tower returns to idle position with the handle in neutral.

 

[TwoFish]

Re: 1992 70hp Force motor cam shaft just a hair forward to much, causing high idle

I think Frank is on the money with the cable adjustment. I'll take some photos and lable them . Will no be able to post them until tomorrow as I am away fishing at the moment.

 

[privfisher]

Re: 1992 70hp Force motor cam shaft just a hair forward to much, causing high idle

Thank you Frank! Thank you TwoFish! Jiggz, All info is very much appreciated. This will hopefully save me a trip to the boat shop tomm. I'm going to take all advice, and try to fix first thing in the morning, so I can hit the lake! Will be looking forward to those pics TwoFish. Again thank you guys!
Good luck fishin TwoFish! Catch some for me

 

[jerryjerry05]

Re: 1992 70hp Force motor cam shaft just a hair forward to much, causing high idle

The throttle cable connector,when installed should have a small bit of tension on it.
They have 2 kinds.one has an internal spring.
The other not.
The internal spring is for the throttle.
If you don't have it no problem.
Just make sure it fits tight.

 

[Jiggz]

Re: 1992 70hp Force motor cam shaft just a hair forward to much, causing high idle

Thank you Frank! Thank you TwoFish! Jiggz, All info is very much appreciated. This will hopefully save me a trip to the boat shop tomm. I'm going to take all advice, and try to fix first thing in the morning, so I can hit the lake! Will be looking forward to those pics TwoFish. Again thank you guys!
Good luck fishin TwoFish! Catch some for me

It will actually help everybody especially you if you can attached photos. Forum members highly recommend posting a photo of issues even for relational purposes only. TwoFish is very good on this and will even have the courtesy to provide arrows and directions in the photo. Frank can usually spot any mal-adjustments based from photos as long as it's clear enough. And for forum members soliciting for help, it makes the discussion linear meaning we all talk the same parts and languages in providing solutions.

 

[TwoFish]

Re: 1992 70hp Force motor cam shaft just a hair forward to much, causing high idle

Hi privfisher

We had a great time and caught some fish as well. Photo below is of a 72 cm Snapper caught on a rod with a size 6 hook on 6 lb line. It took the rod we were using for small fish and left the snapper outfits.

The Idle speed photo is fairly self explanatory. It?s the starboard side of the motor and also shows where the gear and throttle cable are in relation to the rest of the motor.

Unfortunately to adjust the throttle after you have set the idle screw you have to remove the gear cable first. You will need to remove the ?End nuts? first. Then remove the nut holding the gear adjuster and lift the gear cable out of the way. Be careful not to drop the nuts or the bezel type washers as they can be a pain to fish out from the bottom of the cowl. Once you have the gear cable out the way slide the end of the throttle cable off of the end bolt.

Whilst you have all the cables disconnected try moving the tower mechanism by had to see if it moves freely or has any loose or worn parts. You could also move the forward hand control to see if the cable runs smoothly. If all checks out Ok continue with the adjustment.


You will be able to tell if the cable is too long or short by how it lines up with the bolt. To adjust the length remove the adjuster nut from the throttle cable and side the adjuster off the bolt. You then wind the adjuster around the cable to make it shorter or longer. It may be necessary to have this cable slightly on the longer side so it is long enough to return the tower mechanism all the way to the stop position. Once you have the correct length replace adjuster nut and end nut lightly by hand and move the forward hand control to full throttle and back to neutral to see if the moves freely and returns the carb to the idle position. If all is OK replace the gear cable checking the length the same way. Grease the sliding sections of the cable with water resistant grease to finish.

I don?t know of an easier way of adjusting the cables but if there is I?d certainty like to know.

Cheers

TwoFish

 

[Jiggz]

Re: 1992 70hp Force motor cam shaft just a hair forward to much, causing high idle

TwoFish, Deep fried Snapper with Chili Sauce and green onion and a couple of VB's!

 

[TwoFish]

Re: 1992 70hp Force motor cam shaft just a hair forward to much, causing high idle

Jiggz, Very impressed! If you are not an Australian you could pass for one writing thing like that.

 

[privfisher]

Re: 1992 70hp Force motor cam shaft just a hair forward to much, causing high idle

Thank you Two fish! I appreciate the motor pics and the snapper pic. I laughed when I saw the arrow pointing to the snapper. That's Funnny!!! Is a nice snapper though! Yummy! I'm trying to get ready for the Flounder season coming up here when the water gets cooler down here in FL.
I noticed in pic#3 your cam has a line that is lined with the roller. Mine is not, I will do what Jiggz said and shoot a pic of how mine is lined up. If yours is correct setting, Than mine is way off course, maybe thats why spark advance and all seems to be outta whack. Now, as far as your cam, is it an any way resting on your roller at all. I have heard that you should be able to slide a piece of paper between cam and roller. Is this true? I am so close, to having it set good, yet so far.

 

[Frank Acampora]

Re: 1992 70hp Force motor cam shaft just a hair forward to much, causing high idle

Just click on the sticky FAQ, Synchronizing timing and carbs, at the top of the forum page. It will answer all your questions.

 

[privfisher]

Re: 1992 70hp Force motor cam shaft just a hair forward to much, causing high idle


This is how my cam and roller is set up, but compared to TwoFish's motor, mine looks to be way off. It looks like Two Fish,s cam is lined up centered with roller. If I forward my control lever to WOT it opens throttle perfectly horozontil position, looks right to me, but guess is all wrong? Geesh! Brain overload!!!
Note: the #1 pic is my motor in idle position. Cam looks to be off correct?

 

[privfisher]

Re: 1992 70hp Force motor cam shaft just a hair forward to much, causing high idle

The throttle cable connector,when installed should have a small bit of tension on it.
They have 2 kinds.one has an internal spring.
The other not.
The internal spring is for the throttle.
If you don't have it no problem.
Just make sure it fits tight.

I have the internal spring style. I just see one nut towards the end of the cable. Is that the adjustment nut?

 

[privfisher]

Re: 1992 70hp Force motor cam shaft just a hair forward to much, causing high idle

I think I might jus file down the cam, everythings tight, just seems to big and its pushing on roller just enough to open carb.