87 Force 85hp link and sync question

[Unbalanced]

I'm getting close to getting this old engine running like new again, but I have a question in regards to the idle speed screw and the throttle cam.
If I line up the cam to the line on the curved arm, I can't get full throttle. The manual says to adjust the length of the arm to get the butterflies horizontal at full throttle, but then I have to adjust my idle screw all the way in to get 750 rpm at idle in gear - on the water. So now at idle the line on the cam is 3/4" lower than the cam.
I seem to need to bump the idle a touch more. When shifting from forward to reverse, sometimes it quits. Starts right up and idles, but the transition causes it to quit.

Oh, and another question: I installed a new fuel pump kit and after 3 hours of running, it tore. Did I squeeze the bulb too hard or did the SeaFoam attack it? Good thing I ordered two!

FWIW
My compression is 130psi on 1/2 and 128psi on 3
Full throttle runs 5K on a 13.25x17 stainless at 35mph.
Timing is set to 30deg (the middle mark) at full throttle.
De-carb (SeaFoam) has been done 2 tanks ago.
I've cleaned the carbs and installed carb kits. Floats are level when inverted.
I replaced the stator and starter.
Puddle drain reeds and manifold cleaned.
New fuel lines and clamps installed.
New fuel pump diaphram and gaskets.
New Boyesen reeds and gaskets.
Plugs are new Champions.
Battery is new and fully charged. Meter reads 15 volts when charging.
Telltail added.

Thanks,
Jeff

 

[Frank Acampora]

Re: 87 Force 85hp link and sync question

Timing MUST be synchronized with throttles. If timing is too far retarded, then the throttles must be opened too far to get a proper idle.

Start from scratch. With the engine in neutral set the idle stop screw to about 1/2 of its length. Set the line on the cam to contact the roller on the carb. Set the roller so it just contacts the cam. The roller is on an eccentric screw. Loosen the nut and turn the screw. Now moving the two ball ends on the throttle rod, adjust the cam so you get full butterly opening at WOT. You should now only need minor adjustment on the idle stop screw to bring the line back to the roller.

NOW, at neutral, set the timing to zero degrees (first mark on the flywheel). Question: Is the flywheel key sheared, letting the flywheel move out of position? If it is, you will not be able to properly time the engine.

Usually, the gap between the two plastic links on top of the tower will be somewhere around 1/2 inch apart to get zero degrees.

Now it is time to start the engine or set timing at cranking speed. If you set the timing at cranking speed, disconnect the fuel line and remove the sparkplugs so that engine will not start. Using a spark tester, ground the plugs so you do not damage the CD boxes. Using the plastic links and the threaded connector, set the WOT timing to 28 degrees before TDC; it will advance to 30 at running speeds. THIS is the important timing setting.

If you set timing with the engine running on the water in forward gear, set it to 30 degrees advanced at WOT. DO NOT ADJUST WITH THE ENGINE RUNNING. This will color the flywheel red and you will join the nine finger club. Stop the engine, make a small adjustment and restart it. Do this until timing is correct. Note that the plastic timing links should be somewhere near 3/16 to 1/2 inch apart. This is not exact though and some engines will need a larger gap.

Note that with timing properly advanced at WOT, the idle stop screw may need some adjustment for proper idle speed AND timing at idle may be anywhere from minus a couple of degrees to plus a couple.

Zero degrees is only your reference and starting point. It will not necessarily be the correct timing at idle! Also, at idle, the reference mark on the cam will not contact the roller but usually is a little below it. Carbs will usually be just a smidge opened and timing usually about 2 degrees advanced to acheive 750 RPM in the water, in forward gear. However, now you should be able to acheive a good idle speed and full throttle opening.

 

[Unbalanced]

Re: 87 Force 85hp link and sync question

Frank, thank you for taking the time to respond. I've been reading this forum since I bought this boat last November, and your presense and expertise on this thread is priceless. Again, thank you!

According to your reply and the Clymer manual, I have peroformed the proper set up in regards to timing. I'm at 30deg - the middle mark, at WOT. Idle timing is close enough to 0 (since there is only the 0 deg reference) it may be 1 deg or so.

Carb butterfly travel is sync'ed and the idle mix is 1 1/8 turn out.

My question is I have my idle adjustment screw all the way in (screw head contacting the lock nut) to obtain 750 ish RPM at idle. The cam slot mark is about 3/4" lower than the cam.

If I disconnect the throttle cable and move the idle adjustment screw to half its travel therefor bringing the cam closer to the mark on the throttle arm, the idle speed does not drop.

I'm theroizing (sp) that the throttle cable has less travel than the carbs. Is that possible?

Also, any thoughts as to why my new fuel pump diaphram tore?

Thanks,
Jeff

 

[jason32038]

Re: 87 Force 85hp link and sync question

You need to adjust your idle in neutral and check your timing. Keep adjusting and rechecking your idle and timing until they are dead on. Idle in NEUTRAL should be 700-750 rpm and static timing (checking timing by cranking engine with WOT) is 34 degrees. You can then adjust the rod that opens up the throttle a bit when shifting into gear by loosening the nut and rotating the balljoint looking thing clockwise to lessen idle in gear or counterclockwise to increase idle when shifting into gear. Sorry I don't know all the names of the parts.

 

[Frank Acampora]

Re: 87 Force 85hp link and sync question

I would not expect throttle cable problems because the control box does not have a stop. The stop is on the tower link. It is a black button that bears against the block ay wide open throttle. However: Not knowing which control box you have though, I would need to say that it could be possible that you are not getting full throttle cable travel. With some boxes, it is possible to put the throttle cable on the shift lever. If this were to happen, you would not get one gear and throttle would not open properly since shift lever has less throw. This is not a likely circumstance, However, push the control handle only far enough to operate the shift cable and at the engine end, see if the cable is connected to the correct linkage. And ball end--Shift cable goes on the top ball, throttle attaches to the bottom. Note that if connected to the incorrect ball, one is further back than the other.