Throttle Linkage problem - w/Pics

Mark42

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Was working on the linkage of the 85 hp. There are two 3/32" roll pins that hold a lever to a rod that runs the timing and carbs. Both the roll pins sheared off and replacing them has been a real pain because they are below the lower cowl.

The pic below shows the arm with two finishing nails inserted where the two roll pins should be. To get to the point of driving out the pins without removing the power head or cowl, the shift and throttle cables were disconnected and completely removed from the motor. This gives some working space. Not much, but just enough to swing a hammer with a 2" wide head while holding a finishing nail with needle nose pliers to drive out the broken bits.

HPIM6761.jpg


One reason the pins sheared off was because there is a load of stress on them. The timing is advanced, and all three carbs are operated through those two 3/32" diameter pins. To make it harder, each carb has its own strong return spring that adds to the resistance on the linkage.

So, I disconnect the horizontal link with the ball/socket ends to determine if anything was binding or making the assembly harder to move. Turns out the nut just below the right hand ball/socket was tight, making it hard to move move the linkage cam that pushes the carbs open. So backing off that lock nut a mere 1/4 turn made the cam rotate easy, taking a good amount of resistance out of the whole assembly.

HPIM6763.jpg


Next I checked the vertical link that connects all three carbs. It was rather hard to move. Not because its binding, but each carb has its own return spring. By moving the spring end stop from one side of the butterfly lever to the other (let the spring unwind about 140*) to take just a little bit of resistance off the spring. Did this to the top two carbs, and left the bottom alone. In the photo below, the end of the spring is bent over the butterfly shaft lever. This is where I moved it to. It was rotated clock wise and hooked where the number "42" is stamped into the lever. Although its easier to open the carbs, there is still plenty of spring force pushing the carbs closed.

HPIM6762.jpg


I am still looking for 3/32" roll pins (got any?), but if they are not to be found, might cut the finishing nails to the right length, then flatten one end slightly to make a friction fit. But the nails are not as strong as roll pins, so I would prefer to use roll pins.

Thats where its at tonight. A really hard spot to work, but luckily the cables come out easy to make the job a little easier.

For some reason, Force did not cover the disassembly or adjustment of this entire linage in the OE shop manual. Go figure.

I'm going to check Mcmaster.com, but I bet I'll have to buy a bag of 1000 or so if they have them.
 

Mark42

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Re: Throttle Linkage problem - w/Pics

Found the pins on Mcmaster.com. A box (25 pins) of heavy duty, stainless steel 1.5" long pins is $10.17 plus shipping.

They are a reliable and fast supplier, so the pins will be ordered from them first thing in the morning.
 

jason32038

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Re: Throttle Linkage problem - w/Pics

The tall towershaft is very easy to remove. It'll make your job a lot easier. All you have to do is remove the timing screw that connects to the upper shaft. Remove the plastic retainer with the 2 screws and lock ring near the middle of the shaft and pry the bushing out downward at the upper shaft where it goes through the hole in the powerhead. Remove one point of the smaller linkage also so you can manuever the towershaft around it. I think you have to remove the intake cover also.
 

Mark42

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Re: Throttle Linkage problem - w/Pics

The tall towershaft is very easy to remove. It'll make your job a lot easier. All you have to do is remove the timing screw that connects to the upper shaft. Remove the plastic retainer with the 2 screws and lock ring near the middle of the shaft and pry the bushing out downward at the upper shaft where it goes through the hole in the powerhead. Remove one point of the smaller linkage also so you can manuever the towershaft around it. I think you have to remove the intake cover also.

I think the flywheel has to come off too, no? I can't get the L shaped top through the bushing, so it has to pull out the top. And the flywheel covers it up.

Anyway, as you can see the old pins can be driven out by removing the cables, and new ones driven back in the same way.
 

jason32038

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Re: Throttle Linkage problem - w/Pics

You have to pull the bushing down to get it out then the upper linkage will slide down and out of the hole with some manuevering.
 

Mark42

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Re: Throttle Linkage problem - w/Pics

Found the pins on Mcmaster.com. A box (25 pins) of heavy duty, stainless steel 1.5" long pins is $10.17 plus shipping.

They are a reliable and fast supplier, so the pins will be ordered from them first thing in the morning.

Just an quick update.... The roll pins came yesterday and this morning I installed them. Nice snug fit. Although it was a pain to find and order the stainless pins, I think it was worth the money ($15 for 25 pins to my door) knowing they are stainless and 30% stronger than the standard roll pin.

I re-adjusted everything from the control lever to the carbs. Took the time to clean then grease all moving parts with marine grease (I like the stuff from Jonhson/Evinrude), adjust the shift and throttle cable, and all linkage on the power head. Now the throttle lever moves nice and smooth. When at WOT, I have no fear of forcing or bending anything because its all adjusted and stops are set. And now the carbs open full when the control is pushed to the end of its travel. I can hardly wait to hit the water next week! Might make a new top speed record for my boat! Woo Hoo!

BTW, if anyone needs or wants some stainless roll pins 3/32" x 1" just shoot me a pm. I have some to spare!
 

chuckz

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Aug 22, 2004
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Re: Throttle Linkage problem - w/Pics

Mark,

I had a similar problem. You may want to check the rest of the roll pins in that shaft. When I tapped out what looked like good pins I found that they were split length wise.
 

Mark42

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Re: Throttle Linkage problem - w/Pics

Mark,

I had a similar problem. You may want to check the rest of the roll pins in that shaft. When I tapped out what looked like good pins I found that they were split length wise.

I think the center lever has two pins in it too. It appears to be tightly attached to the rod. Did the split pins show looseness or play in your linkage?
 

chuckz

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Aug 22, 2004
Messages
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Re: Throttle Linkage problem - w/Pics

No. I was surprised when i checked them.
 
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