1986 4.3L Mercruiser V6 Knocking noise?

[Chadbud]

Hey guys!

So long story short. I am working on my parents boat that I recently inherited. It's a 1986 Four Winns Horizon 190 Cuddy. Floor has its soft spots but the stringers seem to be in alright shape and the transom shows no signs of weakening. That being said, I decided to tackle the engine first.

The boat sat for 3 years on trailer in storage.. one of those years it sat in the driveway (fully winterized).

I drained old gas, filled with new gas and stabilizers. Pulled all old plugs soaked cylinders with lubricant and hand cranked a few times and replaced with new plugs. (Bosch Platinum +4). Replaced belts and oil. Replaced a few solenoids. Waited a few days.

So at this point I was ready to start her, I sprayed a little starting fluid down the throat of carb and went for it. The trim on outdrive is all the way UP. I get a *click* when I try to trim it down so the solenoid for the down trim probably needs replaced. I decided to try to start her like this anyway. (Mentioned that so maybe it's the u-joint knocking?)

She hesitated for a little bit and then started. She needed throttle to stay idling (expected since she hadn't run in a while) and this knocking was immediately apparent.

It's a very loud metal hammering noise.. like a jackhammer almost. The frequency increased as I gave it throttle and rpm went up.

I'll attach a link to a short video I recorded of it today. Let me know what you guys think!

Thanks!!!

 

[shaw520]

They have trim limiter switches for this very reason,... Keep that trim up and your going to toast your ujoints and maybe more.

 

[bruceb58]

Don't run it like again until you put your drive down.

 

[Bt Doctur]

Your overdue for impeller replacement so pull the drive off and then run the motor with a hose in the water inlet hole

 

[harleyman1975]

Could be U joints knocking from being trimmed too far up. Let it down and try again. if you haven't replaced the impeller you need to now for sure and plan on a complete kit just to be safe...then do not run dry any more always on muffs on hose.

 

[Chadbud]

Okay so it sounds like most everyone thinks I should tackle the trim problem and try it again. So today I'm going to change the bottom solenoid on the pump and give it a go.

Harleyman, I did run it on muffs in the video. Impeller still likely needs replaced.. I just haven't done it yet because I am trying to determine the health of the engine. I'm actually hoping the knocking is from the ujoint because that means it's not something more serious.

I would love more input! So if you're looking at this and haven't put your 2 cents in yet, please do! I could use all the advice I can get!

 

[bruceb58]

It could be something else but since we aren't there, it's hard to tell.

I would be pulling the drive and trying it with the water hose hooked up like Bt Doctor said.

 

[harleyman1975]

We're all boat guys so we hope it is the cheap easy fix!

 

[Rick Stephens]

We're all boat guys so we hope it is the cheap easy fix!

And we are often disappointed :^)

 

[Bondo]

So today I'm going to change the bottom solenoid on the pump and give it a go.

Ayuh,.... Diagnose it, insteada just throwin' money at it Hopin' ya get it right,....

With a stout piece of copper wire, jumper/ by-pass the solenoid,.... Does the motor run,..??
Ya guessed right,...
If it don't, apply battery power to the motor, 'n see if it works or not,....
Blue sky is up, green grass is down,...

Probably just corroded dirty connections,...
Clean 'em all to shiny metal Clean, 'n try it,....

 

[Chadbud]

Thanks for the feedback guys!

I replaced the bottom solenoid but I'm still getting just one "click" when I try to trim down.

So, I'm not sure how to bypass the solenoids. Do I just take a wire and touch the battery positive lead (big red wire/connection) to the Green or Blue wires directly?

Also, I noticed a corroded black wire (looked like two wires glued together) that leads from the trim pump all the way around the transom up to the front of the motor and connects to a terminal where the slave solenoid/circuit breaker is. This wire is definitely no good, but do you guys know what it is for?

Thanks!!!!

 

[shaw520]

that black corroded wire is probably your trim limiter switch,... as far as getting the "down" trim working,? ..read carefully at what Bondo says,.. ^^^^

 

[Bondo]

So, I'm not sure how to bypass the solenoids.

Ayuh,... On the solenoid, there's 2 larger lugs, power in, 'n power out,....

Touch a stout wire to the power in, 'n the power out lugs, you've by-passed the solenoid,...

 

[Chadbud]

Okay so I tried jumping both solenoids while trying to trim up and down and trailer.. nothing works, I get one click each time I try anything no matter what I do. I used small electrical alligator clamps to connect both large posts on each solenoid while testing. This leads me to believe that the black wire leading to the breaker has a play in things. What do you guys think? Is there a way to bypass it and just get the motor to trim down (If it will run that is)?

 

[Bondo]

Is there a way to bypass it and just get the motor to trim down (If it will run that is)?

Ayuh,.... Jumper directly from the battery (+) to the trim motor's green wire,....

If the motor doesn't move, make sure it's grounded,....

If it still don't work, the motor is bad,.....

 

[Chadbud]

Ayuh,.... Jumper directly from the battery (+) to the trim motor's green wire,....

If the motor doesn't move, make sure it's grounded,....

If it still don't work, the motor is bad,.....

Okay, I ran a regular red positive jumper cable from the battery to the green wire on the trim motor. However, nothing happens. I disconnected the thick green wire from the bottom solenoid and clamped the jumper right to it. When you say make sure the motor is grounded, what do you mean? I'm not very electronically inclined so bare with me here haha. I really hope this pump isn't bad or I won't be able to lower drive to see if this noise is just the u joint.

 

[Bondo]

I really hope this pump isn't bad or I won't be able to lower drive to see if this noise is just the u joint.

Ayuh,.... Pull the aft pin from the trim cylinders, 'n let the drive down,.....

 

[Chadbud]

Ayuh,.... Pull the aft pin from the trim cylinders, 'n let the drive down,.....

Okay I think I'm going to try that. However, will I be able to raise the drive back up without the motor if I put the shaft pin back in? Winter is almost here and I have to consider when I'm going to have to winterize it and park it for the winter.

 

[harleyman1975]

Yes just use a floor jack to raise and lower drive with pin removed.

 

[Bondo]

Ayuh,.... The whole drive only weighs 'bout 80lbs, 'n yer not liftin' it, just tippin' it,....

'n you can always just rope it up to the aft cleats,....