Perkins 4.107 Grinds when shifting to fwd or rvs.

[Kokonut]

I haven't researched much into this, having just finished rewiring the boat.

Thankfully, my wiring must be on par as the motor starts BUT if I try to shift it into forward or reverse, all I hear is the gears grinding, and not quite engaging in either direction.

Any suggestions is appreciated.

[Compass790]

Um suggest you say what sort of transmission you have as that will help with narrowing down the diagnosis.

[Kokonut]

Apologies, it's a manual transmission. The gear lever can be moved into forward, neutral or reverse. I have a separate lever for the throttle.

Background: The boat has been tied to the mooring for the past 8 months, unused, while I was working on the re-wiring. Today, I started it with ease and with RPMs at 1200, I shifted the stick forward. But it just grinded without the gear engaging. Likewise with reverse.

[piloto]

That sounds like a mechanical linkage adjustment, nothing to do with electrical. Check the shift lever at the pedestal end and the extension rod at the transmission end. Both will likely extend or retract with a locknut on the shaft/lever.

[Sailmonkey]

It’s a manual? As opposed to an auto on a boat?

What brand is the gear? Or how about a photo of the gear and the shift linkage

[tkeithlu]

Kokonut, let's be specific. Start by reducing the idle speed - the throttle all the way back, and something like 800 RPM rather than 1200. Running well, but no higher than necessary. Then, start testing:

Shift into gear, and see if the problem continues. Back to neutral.

Disconnect the cable at the transmission, and with the engine at idle shift the transmission lever itself into forward, neutral (pause here) and reverse with your hand. If you've still got a problem, it's the transmission, if not it's the cable adjustment.

If it's the transmision, first check for fluid level. Transmissions don't shift well if they don't have enough oil. Top it off, and try again. If that fails, you need a professional to repair your transmission,but that is not likely.

If it works, then it's the cable. Shut off the engine. Put the transmission in neutral and the helm shift lever in neutral. Join the two with the lock nut that goes around the solid end of the shift cable. Then shift the helm lever into forward, neutral, and reverse, checking each time that the transmission lever goes to the right place. In particular, you want to see the the transmission lever goes all the way to the end of it's travel.

You may find that the mountings of the cable at one end or the other are loose, such that there is play in the system, and shifting at the helm does not transfer to full travel at the transmission. Fix that. You should now be good to go.

Aside, always shift firmly and at idle. Do not gradually shift; that just lets the gears grind.

[Kokonut]

Thank you so much for the replies, and I'll take on board the advice from 'Pilato' and 'tkeithlu'. I'll print these and head down to the boat for a diy diagnostics.

Dare to ask, did I misconstrue the question about the type of transmission, I think I did ... I had my 'automobile' hat on.

Neverthess, I will report back and include pics for anyone interested.

As always, very appreciative for this forum and the contributions of assistance.

[Cheechako]

I agree with much of the above:
-rpm low
-possibly the cable isn't pushing the tranny lever far enough, either sticky cable or something like that.

[Compass790]

Originally Posted by Kokonut

Thank you so much for the replies, and I'll take on board the advice from 'Pilato' and 'tkeithlu'. I'll print these and head down to the boat for a diy diagnostics.

Dare to ask, did I misconstrue the question about the type of transmission, I think I did ... I had my 'automobile' hat on.

Neverthess, I will report back and include pics for anyone interested.

As always, very appreciative for this forum and the contributions of assistance.

I was actually wondering if it was a hydraulic trans as only know a bit about mechanical.

But tkeithlu has given you good advice as usual.
good luck with getting the lever throw sorted.

[Minggat]

Are you watching the output shaft fail to turn at idle?
The sound you describe sound like a dampener plate to me.

[John Williams]

Originally Posted by Sailmonkey

It’s a manual? As opposed to an auto on a boat?

What brand is the gear? Or how about a photo of the gear and the shift linkage

May be not auto but my fathers Nicholson 32 from the 1960's had a Borgwarner Velvet drive. A sort of automatic with one gear. But of course it did not change gears for you. But you could at high revs transfer from forward to reverse! in one movement. Pretty spectacular.

[Kokonut]

Hi everyone, have finally boarded the vessel after a long while. I started the engine and surprisingly I was able to engage in forward and reverse without difficulty. I was able to shift from forward to neutral to reverse and back again with no grinding. This gave me an opportunity to travel for about 2 hours, periodically pausing to test the gears once more. The day was a success although very puzzling.

The following week, I jumped on again hoping to take her out, but the problem returned???

I performed the checks as above which were as follows:

. Checked oil level, it is above L and below F while engine cold.
. Started engine, idle is around 700rpm and ran for about 5mins.
. Shifted into forward, neutral then reverse using the lever <gears grinding, not engaging).
. Disconnected the cable at the transmission end.
. Started engine, while in idle, shifted the transmission lever into forward, neutral (paused) and then reverse using my hand <gears grinding, not engaging)

. I did notice a drop of transmission oil (about a drop per sec) from the plastic tube at the transmission end. This normally connects to the Pressure Gauge. It is presently coiled and sealed, disconnected from the Gauge unit.

It does sound like the cogs are jumping sort of smoothly over each other.
When I say 'smoothly', it's not like the gears are jumping and knocking into each other, but sliding over each other. It's not overly noisy.

Someone asked if the output shaft turns while in idle, the answer is yes.
In fact, I can increase the throttle while in neutral and the boat will move forward slightly.

I'm hoping someone could read this and immediately pin-point the problem or throw a few more checks for me to do.

I'm fearing a call to the local mechanic will see a chunk of my savings disappear overnight.

[Minggat]

Still sounds like the dampener plate to me. Common.

[Kokonut]

I'm wondering if this type of work is classed as:

. don't even try it, or
. you really require some experience, or
. a job for the experts

[Uncle Bob]

Originally Posted by Kokonut

I'm wondering if this type of work is classed as:

. don't even try it, or
. you really require some experience, or
. a job for the experts

Hi, what brand is the gearbox ?
If the problem is the drive plate then it is relatively easy to remove the gearbox and replace the plate, if it is the box then take it to a reputable mechanic experienced in marine systems.
If you need a recommendation I would suggest you contact John Wichard, Wichard Marine, he will be able to provide either a solution or point you to someone that will.