1979 johnson 100 hp - what did i do?

[eaganboater1]

i thought i was removing the lower drain screw for the lower unit. i was told by a dealership that it looks like (they didnt see motor, just screw) that this was a screw to hold the shift rod in place. if i take out the screw the shift rod drops and the whole lower unit has to be disassembled.

what is this screw? i can put it back in without incident, but i havent started the engine for fear. how do i know if something bad could happen, or has happened by removing it? my engine manual shows the screw in a figure, but never mentions it's removal in disassembly steps.

 

[bktheking]

Re: 1979 johnson 100 hp - what did i do?

So long as the shift cradle inside hasn't moved, it holds it in place. Take a flashlight and shine inside, it you can see in have a look to see the cradle hasn't moved. If it has post back. The drain screws are slotted, one is below the water intake and the vent screw is above, I can see them in the picture.

 

[Chinewalker]

Re: 1979 johnson 100 hp - what did i do?

No harm, no foul. That screw is a set screw that helps hold and align the pinion bearing. The bearing is a press fit, so removing the screw won't mess anything up. Make sure the gasket washer is still in good shape and put the screw back in.
- Scott

 

[HybridMX6]

Re: 1979 johnson 100 hp - what did i do?

just because I'm curious now, and I'm sure the OP is too, which is it? Shift cradle or pinion bearing screw? Seems like we have 2 separate answers so far.

 

[bktheking]

Re: 1979 johnson 100 hp - what did i do?

There you go, thanks Scott, I learned something new, thought it was the cradle.

 

[bktheking]

Re: 1979 johnson 100 hp - what did i do?

just because I'm curious now, and I'm sure the OP is too, which is it? Shift cradle or pinion bearing screw? Seems like we have 2 separate answers so far.

Pinion bearing, I went to the diagram and sure enough, pinion bearing screw, guess it was a design change.

 

[Chinewalker]

Re: 1979 johnson 100 hp - what did i do?

No shift cradle on the V4s like the 35 hp & under motors. The shift mechanism is at the fore of the gearcase and operates the clutch internal of the propshaft with a plunger, rather than external with a shift cradle.

 

[eaganboater1]

Re: 1979 johnson 100 hp - what did i do?

thanks for all the help people. It sounds like it is a set screw for a bearing, which is good. However, i just got the boat together yesterday and tried to start it. The engine revs wildly and will not idle down. it seems that the choke doesnt pull down? I looked for obvious stuck mechanisms, but nothing is jumping out. any suggesstions on a daignostic?

 

[Chinewalker]

Re: 1979 johnson 100 hp - what did i do?

With the engine off, check the movement of all linkages when shifting and throttling up. Watch for the timer sticking. Everything should move smoothly. If the motor has been sitting for awhile, lubricants can dry out and make things jumpy...

 

[eaganboater1]

will it blow up?

will it blow up?

Guys/Girls,
sorry if this question seems amaeturish. This is my second season with my first boat. i know a 2 cyce can spin up quick. my tach is not functional ( may be i blew the "regulator" - i rewqired the complete boat and replaced the regulator.

When i fireit up, and leave the choke off, this engine spins really high and doenst seem to idle down. i checked linkages and they seem ok. i may be shutting down really early for panic ( about 5 seconds)

is it possible for this engine to run out of control and "blow up" like spinning a bearing? is there some external means to measure rpm off the flyweel? or am i just being a wimp, not remembering the warm up cycle of a 100 hp 2 stroke?

its june here in mn and i would love to pull our boat out of dry dock.


thanks in advance

david

 

[AlanR]

Re: 1979 johnson 100 hp - what did i do?

Does your throttle linkage close your trottle all the way closed?

Also are you running it in a bucket of water or on muffs?

 

[eaganboater1]

dead boat - dang

dead boat - dang

throttle body was closed. watter mufflers on. not knowing the engine well enough let it run. blew a holw in the crankcase size of a dollar coin. dang. lost the job boat was my only release not what? $ 2500 for a case? darn it.