Johnson 2001 90hp clunks in and out on engagement of forward gear

[Iainr]

G'Day All,

First post here!

Motor:
I have a Johnno 2001 2st 90hp.

Issue/Observation
- When in neutral and push forward on the controls, I hear a 'clunk' where the motor momentarily goes in and out of forward gear (i..e it seems to bounce back to neutral). The 'clunk' is bordering on a 'bang' and is noticeably louder than a normal gear engagement. If I repeat the exercise it will 'clunk' again but will eventually (after one or more tries) go into gear. Once in gear it stays in gear and seems to perform normally right through the rev range.
- No issues with reverse gear.
- Forward gear engages ok on the trailer i.e. prop in air- this happens only when the prop is submerged

Other Factors:
1) I recently noticed an oil leak and had water in the gerbox due to fishing line damaging the seal. I removed the prop and bearing carrier assembly and replaced the seals, O-ring and gerbox oil. There were no metal fragments on the drain plug, the bearings looked in excellent condition and there was no evidence of rust internally. The new oil now looks fine and there is no water ingress or oil leaks post repair. The first time I used the boat post repair this problem was not present. It appeared on the second usage.
2) Immediately prior to this problem emerging I replaced the fuel line and therefore removed the engine cowling and the small cover where the cables enter the outboard. The cables have all been lightly moved/jiggled during this process.

Timeline:
Noticed oil leak - no clunk prior
Replaced gearbox seals - no clunk immediately after (single boat outing - multiple gear engagements)
Replaced fuel line - clunk appeared after

Thanks for reading and all suggestions welcomed.

Iain

 

[racerone]

What dimension did you set the shift rod height to ??

 

[Iainr]

What dimension did you set the shift rod height to ??

Sorry mate I don't understand the question!

 

[spybot]

When ever you remove the gearbox you MUST MUST make sure the shift rod is set to a specific height from the gear case to the center of the hole in the shift rod.

On my 1980 V4 CROSSFLOW with a long shaft thew size ie 554.58 +/- 0.91mm This size will not work on your motor !!!

Every model has its own height and within that range will be the height for long shaft & extra long shaft.

If the hole is not set at this height you will have gear selection problems (Like the one you described).

The only fix is to drop the leg and set the shift rod to the mm.
To do this you turn the rod clock wise to reduce the size and anit-clock wise to increase.

 

[Iainr]

Thanks and I appreciate you guys taking the time to reply.

I'm probably missing something but I didn't remove the gearbox. I removed the prop and pulled out the bearing carrier and replaced the seals and O ring.

 

[havoc_squad]

Thanks and I appreciate you guys taking the time to reply.

I'm probably missing something but I didn't remove the gearbox. I removed the prop and pulled out the bearing carrier and replaced the seals and O ring.

What they are trying to tell you is the shift rod that screws into the shifting mechanism in the lower unit has a specified height called out in the service manual.

If you do NOT adjust it per the length in the service manual, your lower unit will not shift correctly.

If you did a proper complete seal job, you would have had to remove the shift rod.

Most times this is the measurement from where the lower unit fits to the midsection and measure to the tip if it is threaded at the top. If it has a hole, then you measure to the center of the hole on the top.

Maybe someone has a copy of the page of the service manual that covers this, else I strongly recommend you try to purchase the OEM service manual.

 

[Iainr]

I repeat .... I did not remove the shift rod, just the bearing carrier in order to replace the prop shaft seals.

 

[spybot]

I removed the prop and bearing carrier assembly and replaced the seals, O-ring and gerbox oil.
Replaced gearbox seals

Normally this would mean replacing ALL the seals ie taking the gearbox OFF the motor. Then replacing the driveshaft and shift rod seals.
This is why we thought you had altered the shift rod height.
Since you left the gearbox on, the only thing i can suggest is that you may have moved the trunion (Spelling ????) that
controls the amount of movement the gear cable has whilst fitting the new fuel line.
Do you have them fully seated and bolted down ???

 

[Iainr]

Since you left the gearbox on, the only thing i can suggest is that you may have moved the trunion (Spelling ????) that
controls the amount of movement the gear cable has whilst fitting the new fuel line.
Do you have them fully seated and bolted down ???

Thanks mate. As per your suggestion my next step is to check the cable and mounting points and ensure it is all aligned. I Thanks for your assistance. It is appreciated.

 

[Iainr]

Resolved: Idle adjustment (was too high RPM) and cable adjustment which was out quite away. Now engages into gear beautifully

 

[oldboat1]

Be sure to snap the unit into gear when shifting -- don't ease it in. Glad you found the problem.