1988 Forcce 85hp Losing 4mph top speed after decarbing???

[jimmbo]

Perhaps you have a throttle cable that has poor connection inside the ends

 

[DunbarLtd]

Perhaps you have a throttle cable that has poor connection inside the ends

Ill be going out Friday to check on those things. I will update when i get back.

 

[Nordin]

When checking the TDC you just verify that the flywheel key is not shared and that the timing plate is correct adjusted to set the timing at WOT.
The TDC is fixed as the grove in the crank shaft and the grove in the flywheel is a fixed point.

You set the static timing by runing the starter if you have the Prestolit ignition system.
Your 1988 85Hp has the prestolite system.

Static 28 dgr ends up with about 30-32 dgr dynamic.
32 or 30 dgr at WOT does not matter, the performance is not notable.

Usually the timing do not change if you do not mess with it (change triggerplate etc).

 

[jerryjerry05]

Checking for TDC just shows the flywheel key's not sheared.
The flywheel nut's held on with 85-90# of torque and the key can shear a little.
But the timing can't change unless you move the trigger.
The linkage can come loose/break and change things.

You check the speed with the speedo or a GPS?
The pitot tube(on the back of the boat) can lift a little and give the wrong reading.

 

[DunbarLtd]

When checking the TDC you just verify that the flywheel key is not shared and that the timing plate is correct adjusted to set the timing at WOT.
The TDC is fixed as the grove in the crank shaft and the grove in the flywheel is a fixed point.

You set the static timing by runing the starter if you have the Prestolit ignition system.
Your 1988 85Hp has the prestolite system.

Static 28 dgr ends up with about 30-32 dgr dynamic.
32 or 30 dgr at WOT does not matter, the performance is not notable.

Usually the timing do not change if you do not mess with it (change triggerplate etc).

What makes you think it is Prestolite vs Thunderbolt? I have 3 cdi coil packs along with the 2 larger packs above the wire terminal block. They are all black. I think I read somewhere the blue ones are prestolite???

What is the obvious difference between the two?

 

[DunbarLtd]

Checking for TDC just shows the flywheel key's not sheared.
The flywheel nut's held on with 85-90# of torque and the key can shear a little.
But the timing can't change unless you move the trigger.
The linkage can come loose/break and change things.

You check the speed with the speedo or a GPS?
The pitot tube(on the back of the boat) can lift a little and give the wrong reading.

Yes I have GPS running. I bought an aftermarket speedo (pretty much just for aesthetics to update all the 80s style gauges that were all faded and barely readable. But yea it is probably 3-4 mph slower than my GPS speed. Im assuming the GPS is accurate.

 

[Nordin]

1988 Force (US Marine) used Prestolite ignition system and when Mercury (Brunswick) took over in I beleave 1989-1990 they started to use parts from Mercury engines, but that was in 1990-1991.

1990-1991 engines can be equipped with either Prestolie or Thunderbolt system.

Prestolite system has three ignition coils and two CDI boxes for a 3 cylinder engine and four ign. coils and two CDI boxes for a 4 cylinder engine.
In the begining the CDI boxes were black and later they were blue.
Aftermarket boxes from CDI Electronics are blue.

Thunderbolt system has the same numbers of ign. coils as numbers of cylinders BUT just one CDI box and this box is black and lager then the Prestolite typ.

I am pretty sure you engine has the Prestolite system.

 

[DunbarLtd]

1988 Force (US Marine) used Prestolite ignition system and when Mercury (Brunswick) took over in I beleave 1989-1990 they started to use parts from Mercury engines, but that was in 1990-1991.

1990-1991 engines can be equipped with either Prestolie or Thunderbolt system.

Prestolite system has three ignition coils and two CDI boxes for a 3 cylinder engine and four ign. coils and two CDI boxes for a 4 cylinder engine.
In the begining the CDI boxes were black and later they were blue.
Aftermarket boxes from CDI Electronics are blue.

Thunderbolt system has the same numbers of ign. coils as numbers of cylinders BUT just one CDI box and this box is black and lager then the Prestolite typ.

I am pretty sure you engine has the Prestolite system.

Well since I have 2 CDI boxes apart from the 3 coils it sure sounds like I have the Prestolite ignition. Thanks for the little history lesson there too. That's why I love this forum. Always learn something. Thank you.

 

[DunbarLtd]

Perhaps you have a throttle cable that has poor connection inside the ends

Well today was super windy so i didnt feel comfortable checking the timing while bouncing around but i did manage to push down on the throttle cam when going full throttle and sure enough i could hear the motor RPM's increase slightly .

So...
Adjust the throttle cable connection at the helm?

Adjust the carbs cam rod?

Adjust the control cable where it connects to motor?

Or simply start over and do a link and sync? I was hoping I could just adjust a cable a little and that would pick up the slack.

Ive done a link and sync after i bought new cables last season. Maybe they stretched out?

Anyways thats the update. Any help is appreciated.

 

[Nordin]

If you did the link and sync correct earlier it has not change.

Unhook the throttle and shift cable, shift into forward gear, advance the throttle to WOT and check the static timing by running the starter.
If the timing ends up at about 28dgr the timing is right.
Check the butterflies in the carbs.
If they are horizontal or almost horizontal then you have to adjust the throttle remote cable as it do not have enough stroke.

The throttle remote cable should have a lager/longer connector which has a spring inside.
You have to preload it when adjusting.
It should have a preload with about 1/4 inch when you hook it up on the ball.

The purpose of this is to ensure that the shifter has done it´s whole stroke before the throttle starts to move.
Dependig what remote control you have there is possibility to adjust the cable in the remote control.

 

[DunbarLtd]

If you did the link and sync correct earlier it has not change.

Unhook the throttle and shift cable, shift into forward gear, advance the throttle to WOT and check the static timing by running the starter.
If the timing ends up at about 28dgr the timing is right.
Check the butterflies in the carbs.
If they are horizontal or almost horizontal then you have to adjust the throttle remote cable as it do not have enough stroke.

The throttle remote cable should have a lager/longer connector which has a spring inside.
You have to preload it when adjusting.
It should have a preload with about 1/4 inch when you hook it up on the ball.

The purpose of this is to ensure that the shifter has done it´s whole stroke before the throttle starts to move.
Dependig what remote control you have there is possibility to adjust the cable in the remote control.

Ok thanks. I think I understand the preload idea but to make sure, once its preloaded will it essentially be harder to PULL onto the ball link or will it be harder to PUSH it onto it? Basically, if it is harder to PULL it I have made the cable too short and too long if I have to push it on. If that makes sense.

Im not sure which way causes proper preload. Perhaps I have hooked it up with the preload backwards, causing slack?

 

[jerryjerry05]

They made 3 different cable ends.
The shortest one was for the shift cable.
The others were for the throttle.
You might not have the one Nordin described, both have 1 spring inside the other
has 2 barrels, both have springs.
One that Nordin describes wasn't used on all outboards.
Post a pic of the cable ends??

The pre-load shouldn't be too much.

 

[DunbarLtd]

They made 3 different cable ends.
The shortest one was for the shift cable.
The others were for the throttle.
You might not have the one Nordin described, both have 1 spring inside the other
has 2 barrels, both have springs.
One that Nordin describes wasn't used on all outboards.
Post a pic of the cable ends??

The pre-load shouldn't be too much.

I have the Teleflex 3300 cables with the spring loaded ends you have to pull back the outside sleeve part to expose the hole on the cable connector and then while keeping it pulled back, snap it onto the ball link. Then after its connected you let go of the outer sleeve and it slides back over the ball link, covering the connection basically. I believe there are springs inside those connectors. Sure feels like it. Both cables have them.


BUT....your reply still doesnt answer my question so I will try again.

When you are setting "preload" on these cables in order to connect to the ball link, do you make the cable a little shorter(by spinning the barrel nut) or do you make it a little longer?

Making it shorter means I have to PULL on the cable with a little effort to get it to snap onto the ball link. The other way makes the cable longer and I have to PUSH it onto the ball link.

Which way if the correct way? I was trying to use common sense when doing it myself and I just got confused. LOL So I may need a little help understanding this small detail, which seems to make a big deal in the functioning of the cable.

EDIT: I have searched other forums and am not sure if it relates to my issue but I will post here what is said:

"Both the inner and outer cable needs to be secured at each end. Especially the outer cable. Have a good look at the brackets the outer cables secure to. Are they secure?

When you know that this is all good, pop the inner cable socket off the engine end, check the throttle is closed at the helm, then check to see if the socket lines up with the ball on the throttle body. The center of the socket should be about one sixteenth of an inch past the center of the ball, to ensure when the throttle lever is closed the throttle is positively closed. Now move the throttle lever to full throttle. Open the throttle body lever to full throttle and the ball should line up perfectly with the socket.

If the socket is past the ball you are trying to bend the throttle lever at full throttle.
If the socket is before the ball, you have just found some more horse power because you are not getting full throttle.

Let's know how you get on."

 

[DunbarLtd]

I figured it out. Adjusted the jam nut out some took the slack out.

 

[Nordin]

The throttle cable should have a longer spring loaded connector and the shifter should have a shorter connector without spring load.

You adjust the throttle cable by the threaded end of the cable so the distance from the center of the ball to the center of the hole in the connector is about 1/4 inch.
You have to pull the connector 1/4 inch and at the same time slide the barrel to expose the hole and connect it to the ball.
Fasten the connector by the jam nut .

The shift cable should not have a pring load connector and you adjust it so the hole in the connector lines up with the ball.
Neutral at the remote control and neutral at gear shifter then hook the connector to the ball.

Check by shifting the remote control into forward and then back to neutral.
The gear should shift back to neutral at the gearcase..
Turn the prop clockwise when shifting to ensure the clutch dog to engage the jaws in the gear.

If everything works out good then fasten the jam nut at shift cable..
If not you may have to fine tune the shift connector to the cable.

 

[jerryjerry05]

It sounds like he has the single barrel connectors.
1 short, 1 long.
Adjust so it's a tiny bit short and pull it over the ball.

ALL 3 connectors have a spring in the end.
The kind with 2 barrels will have 2 springs.

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[DunbarLtd]

It sounds like he has the single barrel connectors.
1 short, 1 long.
Adjust so it's a tiny bit short and pull it over the ball.

ALL 3 connectors have a spring in the end.
The kind with 2 barrels will have 2 springs.

Heres what I have. I used the old connectors when i bought new cables. One short one long like Jerry said. I had some slack in the throttle cable and was not getting full travel on the timing tower and the cam. I believe I have it tight enough now. I left the barrel nut a little short and had to tug on it to get it onto the ball stud. Which is easier said than done.

Also took the control box off and adjusted the throttle cable connector so i had to pull it tight into the arm on the control box. But not too tight. If I adjusted it too tight it created too much preload and made it difficult to keep it at wide open throttle. It has a tension screw to help with this but i found a happy medium between the two. Just enough preload and just enough tension so it isnt too hard to push the handle forward. So just maybe a 1/16" - 1/8" shy of the hole on the arm. The gear shift cable connector seemed ok with very minimal slack.

I am not sure how short i adjusted the throttle cable connector on the ball link at the motor. I just kept adjusting and connecting and testing until i felt there wasnt too much preload and removed all the slack. There wasnt much to begin with. I think I only had to spin it one revolution so it was close. I believe the control box adjustment helped as well.

Just have to wait til the wind stops so i can test again on the water. Thanks for the help guys. I am learning as I go and your input always is appreciated whether you realize it or not.

 

[jerryjerry05]

Shift adjustment:
Shifter in N (wiggle the handle)
Lower unit in N (spin prop)
Then adjust the connector so it slides over the stud.
No preload.

 

[DunbarLtd]

Shift adjustment:
Shifter in N (wiggle the handle)
Lower unit in N (spin prop)
Then adjust the connector so it slides over the stud.
No preload.

OK. Ill check that out as well.

 

[DunbarLtd]

Shift adjustment:
Shifter in N (wiggle the handle)
Lower unit in N (spin prop)
Then adjust the connector so it slides over the stud.
No preload.

Hit the lake again today. Still not working right. Im not sure what the issue is. I adjusted cable as tight as I could get it and it still has lost that top end speed.

It starts and idles perfect. Doesnt miss or anything like that. When I floor it, it goes. Just not getting top speed for whatever reason. Maybe start over completely and do link and sync? Im not sure.