1996 90HP Force new noise...

[jasonsinGA]

Hello all! I've lurking around these forums for a couple of months now, and am now stumped. First I'd like to say thanks for all your help so far! So I've got a new to me 1995 Astro bass boat with a 96 90hp force on it. The boat sat under a carport for the past six years. I have cleaned the carbs and replaced the spark plugs on it. I recently went through a timing and carb adjustment that I found on this forum and the boat was running great until today. We were at the lake and after floating for about an hour we went to take off and hear a new knocking/rattling noise, but it only happens when the boat is in gear. I took a video of it and below is a link. If anyone has any ideas on what this could be I would be VERY thankful! Also I am by no means a mechanic, but I do try my best to do things myself and not take them to a professional if it can be avoided. Thank you again for all your help so far!

https://youtu.be/EpRAYDStE6w

 

[Jiggz]

You need to do more diagnosis run. Try running it in reverse and see if the same knocking can be heard. If you cannot hear the knocking in reverse, it could just be a simple adjustment of the shift rods meaning when in forward the clutch is not fully engaging but fully engaged in reverse. However, if the same sound can be heard in reverse, you need to drop the LU and inspect the drive shaft bearings, water impeller, etc.

 

[jerryjerry05]

Does it do it when running fast?
Unhook the shift cable while underway.
Then shift by hand.
If it still knocks then the clutch dog might be bad.

 

[jasonsinGA]

Ok , so I hooked it up to hose this morning to do more diagnostics and there is no noise in forward or reverse. Any ideas?

 

[Frank Acampora]

Some auto stores have twc-3 but you should be able to get it cheaper at Wal Mart. Most Wal Marts anywhere near water have a marine section and they also sell trailer wheels and tires.

 

[jasonsinGA]

Took it to the lake for more testing and noise is definitely only when going forward and it speeds up a little with speed but not a lot.

 

[Jiggz]

You need to make sure the shift rods are properly set. If you disconnect the upper shift rod from the bottom one, you can manually shift (with motor not running on the driveway) the bottom rod. All the way down is the reverse while the all the way up is the forward. Do this and manually turn the prop to make sure the clutch are fully engaging. The prop turns clockwise in forward and CCW in reverse. Mark the two settings with a marker on the LU and in the middle will be the neutral position. Reconnect the top shift rod and make sure when shifted either in neutral, forward or reverse that is hits the marked settings on the LU. If not adjust accordingly.

 

[jasonsinGA]

You need to make sure the shift rods are properly set. If you disconnect the upper shift rod from the bottom one, you can manually shift (with motor not running on the driveway) the bottom rod. All the way down is the reverse while the all the way up is the forward. Do this and manually turn the prop to make sure the clutch are fully engaging. The prop turns clockwise in forward and CCW in reverse. Mark the two settings with a marker on the LU and in the middle will be the neutral position. Reconnect the top shift rod and make sure when shifted either in neutral, forward or reverse that is hits the marked settings on the LU. If not adjust accordingly.

I tried this but it appears the shift rod turns. Is there a way to disconnect the upper from lower and manually shift?

 

[Jiggz]

Post a pic of the shift rods where it joins the upper rod to the lower rod.

 

[jasonsinGA]

sorry for the delay in getting back. Tried posting pics from my phone but they were too big. Anyway got it out and looked at it this weekend. Found the drive shaft has a few missing teeth on the pinion and also the forward gear assembly is broken. Guess its gonna be out of the water for awhile now until I can find the parts at a reasonable price. Thanks for the help everyone!

 

[jasonsinGA]

One more question. The spring on the clutch dog is begining to get loose, would you go ahead and replace it as well?

 

[Jiggz]

Rebuilding LU gear housing is not something easy to accomplish. Most of the time you'd be better off looking for a rebuilt LU or a used one from the boat yard.