1992 Merc 75hp 3 cyl sitting over a year

[Ride.race.live]

Hey ladies and Gents,

So a buddy and I just recently picked up a sea ray 160 with a 75 merc on it thats been sitting for the past year and a half or so.

We have a couple plans for it.

For starters we will be removing the oil injector system and doing our own pre mix. I had already read on here that we just need to remove the shaft and gear and reinstall the pump is this the correct method? I know other motors have "bypass" kits but doesnt seem like this one does.


We will be flushing the oil from the lower end a couple times until the oil comes out clear.


Will put in new plugs as well.


Is there anything else we should look at while in there? the motor does start and seem to run fine but want to do some maintenance on it and give it a good look over considering it hasnt been used much the past 5+ years and sat the last year and a bit.

ill also add its been properly stored and the motor is more or less spotless considering the year


Thanks!
Jesse

 

[Sea Rider]

We will be flushing the oil from the lower end a couple times until the oil comes out

Once finishing draining old gear oil, placen new oil bottle noozle on top oil port and squeeze liberaly new oil while spinning prop untill clean oil comes throughout lower port. Being a 2 stroke engine and before changing new plugs squirt power tuner carbon remover through each carb throat while engine is at fast idle at neutral. Follow can instructions.

Once finished, go for a 1-2 min wot spin as if stealing the combo to burn power tuner leftovers on combustion chambers and exhaust as well, then can install new plugs set.

Happy Boating

 

[Ride.race.live]

awesome thanks for the tips!!

any chance you know what plugs they run on top of your head? I maxed my cell data and my work computer wont let me DL the service manual and hoping to do a pit stop for some stuff after work.


Thanks!
Jesse

 

[DavidMoore]

My recommendations


First thing to do is a compression test.
Then
Invest in a service manual.
Then
Refresh all the lubrication.
Fit a new impeller even if the old one still looks fine.
Check all the fuel hoses are in good condition and not swollen / gummed up on the inside.
Check the electrical connections are corrosion free and tight.
Choose NGK plugs over the champions.

Optional
If you feel the need to do more / want the assurance that it will stay running great:

Consider doing a pressure test on the lower unit, and for sure do this if the oil was not clean.
Consider stripping and cleaning the carbs and rebuilding the fuel pump.
Also there is a possibility that condensation has formed in the starter motor, you could strip it and clean out any carbon dust and corrosion.

That's a great engine you have, looked after properly it should give you years of fun.

 

[Ride.race.live]

all generally easy stuff to go through no doubt!


As for the "new impeller?" which impeller are you referring to? the oil pump one or the actual lower end impeller? what would be the reason to change it even if its visually ok?

ill have to do some searching and see how a pressure test on the lower end unit,


I think we lucked out with the guy properly storing because so far the interior of the motor is more or less spotless.

 

[DavidMoore]

No Title

The water pump impeller, it's rubber and recommended you change it every year or 2 years at the least.
The consequences of not changing it can get very expensive, very quickly.

Attached is how to do the pressure test

 

[Ride.race.live]

awesome thanks for all the help!


I have one main concern right now that I noticed with the motor...


The prop has excessive play... not just sliding up and down the shaft but "wobbles" on the shaft... the shaft is solid in there but the prop isnt. Any ideas?

Seeing the shaft doesnt seem to have any play, is it common for the hub kit and or prop to just be finished / worn?

 

[DavidMoore]

Are you sure?

The propeller should not move on the propeller shaft. If the propeller and propeller shaft move together in a forward and aft direction it's normal

rotational movements are as follows:

With the engine in forward gear the propeller should ratchet when turned clockwise, resistance should be felt when tuning propeller counter clockwise,
with the engine in neutral the propeller should be free to rotate in both directions,
engine in reverse gear resistance should be felt in both directions.

If the engine is in reverse and you can rock the propeller slightly in either way before feeling the resistance it's normal.

 

[Ride.race.live]

Thanks! I took the prop off shaft was straight ect and good condition..

I re tq'd it on and the prop is solid now, I guess previous guy put the prop on and either didnt tq it down or didnt latch down the locking washer and the nut got loose.


I had previously checked the nut before jumping the boat and it was tight... but I guess the nut was "seated" on there solid as I had a hard time breaking it loose to loosen but was just not tight to the prop.


Regardless everything is tight and seems to be in order mechanically! should be taking out the oil pump gears this weekend.

I drained the LU oil and it wasnt half as bad as I expected, was a touch dark but still had a decent clean oil color considering it sat for so long. I used a full qt to flush / fill it and ill prob do a refresh after a couple tours just to ensure its all nice and clean in there. might be over kill but im pretty anal about my stuff to an extent.



Thank you everyone who posted was all very helpful information!

 

[DavidMoore]

Probably no need to do a pressure test then.
One word of warning. Because the engine was well maintained the oil was probably refreshed when the engine went into storage. That would be good maintenance practice and the normal thing to do when winterising the boat. That oil might not be telling you the whole truth if it's new..
After a couple of tours I would just crack open the oil drain plug slightly, if the oil that seeps out is still nice and clean I would leave it as it is. But it's your engine so do as you think best.
If you do decide to refresh check magnet on the drain plug for metal slithers. No slithers and you have yourself a winner.


Have fun

David

 

[Ride.race.live]

awesome sounds good!

Yea I checked the magnet end, didnt seem to have any shavings or slithers thankfully, had a bit of dirty oil on it from sitting about it.


Yea definitely want to re check the LU oil after a few rides.. I think after a few tours thats where we will really break up any of the sediment that settled.. spinning the prop did help get the oil moving a little in there but far from enough to really effect the scrap that settles and builds up.


Hopefully be able to see how she runs by end of the weekend.

 

[DavidMoore]

Post pictures or we won't believe it

 

[Ride.race.live]

hopefully everything falls into place... and can go for a rip

i also wasnt able to find the recommended cleaner to run through the motor so i just picked up a can of sea foam that i was going to run through it.


also damn happy i went over thw motor.. fuel lines are in good shape but all the oil lines where roted n cracked... oil was leaking slowly.. but in sure with the vibration they would of fully broke n fubard the motor



shaft n impellar removed, new lines on oil bottle even tho we wont personally use it...

 

[Ride.race.live]

Here's a pic of the boat actually out on the water.... wish the trip out would of been a little better off though!


If anyone coming across this thread 1st has time and ideas on my issues please see the link here for a clean write up!

http://forums.iboats.com/forum/engi...p-mercury-running-issues-constant-beeep-alarm