Sport Jet 90 Throttle and Oil Pump Linkage problems

Daremo

Seaman Apprentice
Joined
Apr 13, 2008
Messages
42
I am posting this in 3 different forums because Force originally made this motor, then Mercury Marine made it, and finally because alot of jet knowledge is in the PWC forum.

I could REALLY use some help with this, I have been working on this same issue for over a month now and its driving me nuts. If you know anything about this procedure, PLEASE reply.

I am still stumped by my throttle linkage on this engine. Its a 1995 Sport Jet 90 sn OE100528. I have the Mercury Marine Service Manual for this motor.
In adjusting the linkage for this, I have continually run into the same problem. I can get to WOT but I cant get to Idle or I can get to Idle but the linkage wont move far enough to engage WOT.

The manual steps through the following procedure.

1. Adjust the Idle Stop Screw to 1/8" gap between head of bolt and stopnut.

2. Adjust throttle pickup point to mark on cam aligning with the center of the roller.

3. Adjust WOT with engine not running. Ensure the Throttle shutters are +/-5% from horizontal. If not, then adjust the WOT Stop Screw to obtain +/-5%(here the manual does not make sense, it talks about a WOT stop screw opposite the Idle Stop Screw, but there is only a plastic rivet in its place on the arm. I have seen parts diagrams for this tower shaft and they all show the rivet, so i think the manul is in error?)

Oil Injection Pump. With throttle at WOT, adjust Oil Pump Linkage until last mark lines up with another mark (image in manual).

My problem is this. When the Oil Pump Linkage is NOT connected, I can adjust the Idle and WOT settings to be right on. When I connect the Oil Pump Linkage with the throttle set to WOT, I have problems. WOT lines up just fine for the oil pump, but when I go back to Idle, the Oil Pump PREVENTS the linkage from returning to idle, its hitting the rear most amount of travel it has, it cant back any further.

So, I am wondering if someone put the wrong parts on this thing. Specifically
I am thinking perhaps the towershaft is wrong??? Here is why. The spec for the F1820 screw (pn for the idle stop screw) is 1/20 x 1.375. The screw thats in there, is a bolt, not a screw and its METRIC. Its a M5 and it was longer than 1.375". I put in another m5 that I cut down to 1.375" and installed that. It still doesnt correct the linkage issues. So I am at a loss.

Anyone have any ideas?

Thanks!
Rob
 
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