I'm just about ready to sink it.

[NextBestThing]

1998 70 hp Mercury Bigfoot
Previously ran fine & everything was in working order until a bearing blew and dinged up a piston.
Removed upper unit and replaced bearing, 1 piston, 2 solenoids & starter.
Runs beautifully EXCEPT... when controls are in FWD, boat travels in reverse & when in REV, boat travels forward.
Photographed all linkage prior to disassembly & everything is reconnected EXACTLY as it was.
I cannot figure out what the problem is. Obviously something was reassembled improperly but what could it be???

 

[alldodge]

Photographed all linkage prior to disassembly & everything is reconnected EXACTLY as it was.

Welcome
If it was exactly the same it would work the same.
Did you swap the throttle cable with the shift cable?
Put in throttle only and see which cable moves

 

[NextBestThing]

Welcome
If it was exactly the same it would work the same.
Did you swap the throttle cable with the shift cable?
Put in throttle only and see which cable moves

"If it was exactly the same it would work the same."
HA! YOU WOULD THINK!! but here we are lol.

Just to satisfy curiosity, and rule out the obvious, have tried both cables in both positions.

 

[alldodge]

Hey @Texasmark or @racerone have any suggestions?

 

[flashback]

Well it is a good theft deterrent.

 

[jimmbo]

Unless there is some other itty bitty detail that you haven't mentioned... it sounds like like the Linkage between the Connector, and the Shift Shaft got reassembled wrong.

 

[racerone]

Was the lower unit off for water pump work ?-----It should have had a new impeller installed if you did piston work.

 

[NextBestThing]

Was the lower unit off for water pump work ?-----It should have had a new impeller installed if you did piston work.

Negative. We only removed the upper unit because the motor was mounted on the boat, and the boat was in the water. Did the work and reinstalled everything exactly the way we found it.

 

[alldodge]

Post some pics, it might give some insight

As a non-expert
With shift handle in neutral, disconnect the throttle cable off the carb. Can the carb be opened to WOT by hand?

Thinking there is a piece that keeps the carb from opening much at all when in neutral.

 

[Chris1956]

The shift arm under the carb should be facing port, when the shift slide is in the center of the slide track. That should be neutral.

When the throttle handle is in neutral, the cable that is extended the most is the throttle cable. The shift cable will be about 1/2 extended.

When you move the throttle handle from neutral to forward, the shift cable will move first, and get shorter. After the shift cable stops moving the throttle cable will start to move and get shorter.

 

[NextBestThing]

The shift arm under the carb should be facing port, when the shift slide is in the center of the slide track. That should be neutral.

When the throttle handle is in neutral, the cable that is extended the most is the throttle cable. The shift cable will be about 1/2 extended.

When you move the throttle handle from neutral to forward, the shift cable will move first, and get shorter. After the shift cable stops moving the throttle cable will start to move and get shorter.

Very good info - will confirm this weekend!

 

[QBhoy]

Hi. I’d start with the easy one to rule out first. Is it possible that you have a left hand prop on a right hand conventional unit ? Or do you have a conventional right hand prop on an engine that was once the port engine (and counter spun left hand) on a twin engine boat previously?
Send us a wee picture of the prop

 

[NextBestThing]

Hi. I’d start with the easy one to rule out first. Is it possible that you have a left hand prop on a right hand conventional unit ? Or do you have a conventional right hand prop on an engine that was once the port engine (and counter spun left hand) on a twin engine boat previously?
Send us a wee picture of the prop

Everything was working properly prior to the repair. Prop & control were not changed.

 

[racerone]

Did the shift rod lift out of the exhaust housing at any time during the repair, yes , no or no idea ???----Any kids around playing with stuff ?____I would remove lower unit now.-----Install a new impeller.-----Put control in neutral.-----Put lower unit in neutral.----Assemble.-----It should again drive you forward in forward.-----This is all easy if you understand how the shifting works.

 

[Chris1956]

Also, when you removed the powerhead, the shift lever could have lifted enough to separate the splines. They are only held down by the shift slide and linkage. If the shift slide rubber was stuck in the shift slider, the slider is bolted to the powerhead and could have pulled it up.