Any tips on reviving old outboards?

I've been trying to get things arranged so I could put some effort into redoing the transom on my grandfathers boat. Only thing is, the more and more I mess with it the more and more I find that is going to have to be cut out and replaced. Got to looking around on C-list the other night and about laughed my tail off when I found my grandfathers boat minus the engines, electronics, out riggers, etc for sale two hours away from me for about what I'm looking at in wood alone, not to mention resin or glass. Showed it to my dad, and his comment was, lets see if we can get those motors fired up, if so lets go look at it.

So got to looking that the motors last night. They're a pair of 86' Suzuki DT75's. They've been sitting for about 19 years, and I'm pretty sure my uncle decided about 12 years ago he was going to try and get them running due to the silencer assemblies being off of the motors, and seemingly AWOL at the moment. Besides a doing carb rebuilds on both of them, Water pumps, there is debate between dad and I on doing foot seals(I say yes, he says they don't need it), foot oil changed, I'm sure there's more but off the top of my head, that's what I've got.

Throttle butterflies are all opening and moving, and the props spin freely in neutral and lock when put in fwd or rev. The oil injection tanks are still 3/4 full, it doesn't look like there is any water in them, and it smells like old two stroke oil. My worry is that they are locked up. I pulled one of the flywheel covers and wasn't able to turn it by hand with the plugs still in, now I'm not saying that's all I need for proof that they are locked up. But I would hope I would be able to move it somewhat by hand. (just realized while typing that last line, they are 2 stroke, so there is almost always, always going to be at least 1 if not 2 cylinders on compression, **** 4 stroke mentality :grin)

Anyone know if a MMO or ATF soak might help get things moving on an engine that has been sitting this long? or would it do more harm than good? I'm not afraid to take them apart, but I don't want to have to do a ton of unessesary work. I'm worried about rings being frozen etc. I know I'm going to have to change the oil, then change it again in a mater of about 5-10 hours likely just due to crap being knocked loose and wanting these to stay as reliable as they used to be. (These were one of the few "new" purchases my grandfather made. I really would like to keep them around and keep them running.)

And Louie and Marrio, if this is in the wrong area, I'm sorry. I didn't see anywhere that might be appropriate for this kind of post.


  • Jim311Jim311 Posts: 4,929 Captain
    Squirt some two stroke oil or fogging oil into those cylinders and let it sit a few days, that way if you try to turn it over with a breaker bar you won't score the cylinders or damage anything.
  • capt louiecapt louie citrus countyPosts: 9,962 Moderator
    This is exactly where to ask. I'm with Jim311 as far as loading up the cylinders with oil. Marvel mystery or whatever is out there along with a good long soak before trying to turn over.

    There have been motors a lot older than those that have come back to life.
    "You'll get your weather"
  • BillyBilly ChassahowitzkaPosts: 2,705 Captain
    It's a two stroke. They are "almost" indestructible.

    Soak the cylinders as mentioned and it should be fine.

    Take the plugs out after the soak and turn it over a few times.

    The key is keeping the rings from seizing and if it breaks free, and it should, then spark, fuel, and you're good to go.

    "And the ocean is howling for the things that might have been..."
  • Fishin RodFishin Rod Posts: 2,620 Captain
    Pull the plugs, tilt the motors up and fill the cylinders with PB blaster. Let them sit awhile and then put a wrench on the fly wheel nut and try to turn them.
    "Be what you is"....... Isaiah Minter
  • Little_GeneLittle_Gene Posts: 371 Deckhand
    Thanks guys. I'm glad my instincts were on the mark. Maybe when this rain lets up, I can get out there and get this process started. 2 strokes are new to me, so this is going to be a bit of a learning process.

    Thanks again!
  • relicshunterrelicshunter Posts: 596 Officer
    after 19 years I would recommend you change the fuel pump and I highly recommend a new water pump.
  • Fish HaidFish Haid Posts: 8,346 Admiral
    Here is a link that might help:

    Yes, by all means - change the oil - need help finding the oil drain plug? Change the gear oil while you are at it.

    You absolutely need to take carbs apart and clean thoroughly! Well, make sure the powerhead is free first - otherwise wasted effort.

    Reseal the LU AFTER you get the motor running.
  • Little_GeneLittle_Gene Posts: 371 Deckhand
    THANKS Fish Haid! That one is a bit easier to use than the one I've been looking at that has them all together in one shot.
  • BillyBilly ChassahowitzkaPosts: 2,705 Captain
    I'm not sure what you meant by old crap would be broken loose and you would have to change it again but there isn't any crankcase oil in a two stroke

    The oil injection container should be drained and new two stroke oil put in, and run the motor with a pre-mix at first, to ensure the oil injection pump is working. The oil in the lower unit should also be has been mentioned.

    "And the ocean is howling for the things that might have been..."
  • Little_GeneLittle_Gene Posts: 371 Deckhand
    Billy, I'm used to 4 stroke car engines, when reviving old engines that have sat for awhile, we (my friends and I) tend to do an oil/filter change before running them, and then again in 1000 miles or so. Just to make sure any sludge or bits of rust and corrosion don't clog the works too badly. I am admittadly a "NEWB" when it comes to outboards. Not afraid of tearing one apart, but I am definately going to ask questions and do my research before doing so. I had noticed I couldln't find a dipstick, or drain for the crankcase, that would explain it. (though the idea of the oil being supplied by the injection was starting to dawn on me before your post) I may just go back to my rotary habits and just run premix for awhile till I can be sure the injection system is working.
  • Little_GeneLittle_Gene Posts: 371 Deckhand
    Got to play with them some more this weekend. I got one tilted up using the tilt/trim motor, the other started to come up, and now just clicks when you push the button to tilt it up. I'm afraid to use to much brute force to tilt it up due to how rotten the transom is. I litteraly leaned over the back of the boat, put a hand on the top of one of the motors before they were tilted and saw the transom bow out. So I make sure I put as little stress on that area of the boat as possible for the moment, as I need to get off my butt and build a pair of stands for these engines so I can dismount them.

    I've got one engine soaking, the other I squirted a few ounces into each cylinder and spun the the plugs back in as quickly as I could without cross threading them. This afternoon makes 48 hours on the engine that is tilted up, I'm probably going to grab some more MMO on the way home from work and get some more in there. and try to turn it over come Wed. evening.

    2 strokes use "reed" valves right? Will soaking them in oil hurt them?

    Was happy to see all the gauges light up and come to life when I put a battery on them, including the oil level sensors. So there is a plus there!
  • Little_GeneLittle_Gene Posts: 371 Deckhand
    Well... I went out last night with the intention that the one motor I had been soaking was going to turn over. Breaker bar, impact socket, 6' cheater bar. Pulled the plugs, then the flywheel cover. In the process of pulling the flywheel cover I dropped a bolt so I knelt down to find it in the leaf pile. While I was getting up I put my hand up on the flywheel to stand (bad knees), and the **** thing just spun like there was nothing to it. I reached over and gave it a hard spin and shot a stream of MMO 6' behind the boat. So I put power to the motor, trimmed it down, and grabbed a can of starter fluid. Tried the starter, it only clicked and wouldn't engage. So I wrapped the flywheel, and gave her a pull to clear any of the mmo out of the cylinders. Put the plugs back in, and gave it another pull just to see if I could hear it trying to fire off. Yeah, I'm a newb with boat motors, pulled the same way I did with the plugs out. About snatched myself right off my feet. (COMPRESSION IS GOOD!) So opened the throttle all the way up, gave each one a healthy shot of starter fluid, dropped it back into neutral, set my feet, and spun it as hard as I could.

    IT LIVES!!

    Well momentarily anyway. I was happy. If I hadn't been standing in a boat I was afraid I would going to go through the floor on, I might and busted out a little riverdance or something. I'm kidding, but I did give a bit of a victory yell! Picked up the tools and called it a night. Gotta get my hands on a tank, and some premix.
  • Little_GeneLittle_Gene Posts: 371 Deckhand
    Thanks for the help and advice so far guys.
  • Liquid TheropyLiquid Theropy Posts: 608 Officer
    Sweet!! Always good to here old motors run again. Clean those carbs and new water pumps. Also please no more either on a two stroke. Two stoke tend to like oil in there fuel:grin
    [SIGPIC][/SIGPIC]AKA Flatheadcat
  • Little_GeneLittle_Gene Posts: 371 Deckhand
    Yeah I considered that, epecially since I've used ether as a stand in solvent/cleaner. I was curious to see if would kick over, still lots of MMO hanging out in that motor though. I filled two cylinders to the point of coming out the spark plug holes, and 1 to the point of coming out the carbs. I know I didn't get it all out with a couple of pulls.

    Did enough digging online last night to find out where the manual release plug is for the tilt/trim system for the port engine. Hopefully will get it tilted up so I can get it soaking. It's all but loose, I can move it back and forth a bit by hand via the flywheel, just needs a little more. After looking a the service manual for the system I'm betting I've got some bad silenoids (sp?) for the system. Tempted to try 12v straight to the motor but I'm not 100% sure about how the wire harness is ran, and the location for everything yet. Trying to wait till after the next semester starts for my wife before spending the money for the water pump kit and the carb rebuild supplies.

    Will probably pull the starter and try to make sure the brushes/armature are clean and free on the one I have moving this week. It clicks, just doesn't spin and engage. Would be nice to not have to try and pull start it.
  • capt louiecapt louie citrus countyPosts: 9,962 Moderator
    That's awesome ! Hope the other fires as easy.
    I wouldn't think solenoids would go bad from sitting ? IDK
    "You'll get your weather"
  • Jim311Jim311 Posts: 4,929 Captain
    Run 12 volts from a jumper cable straight to the hot wire on the starter. If it spins, you've got a bad starter switch, solenoid, neutral safety switch, battery cable, or wiring to any of the above.
  • Little_GeneLittle_Gene Posts: 371 Deckhand
    I've tried that, just clicks on both.
  • Jim311Jim311 Posts: 4,929 Captain
    Sounds like the starter is all locked up with corrosion or something if it won't move at all with plenty of amps delivered right to the post with the larger gauge cable comes in. There's a place called D+K rebuilders in Alachua that does good work with starters and alternators, they've done a bunch of them for me over the past few years. I wish I'd used them instead of buying a sorry **** remanufactured one on Ebay. Their work/quality is way better than most of the remans.
  • Little_GeneLittle_Gene Posts: 371 Deckhand
    I'll check em out. I've used the place over on nw 6th st and 10th ave in Gainesville for alt rebuilding. Fast work, and it was still kicking along 3 years later when I sent the car down the road, pricing that was a third of a new/rebuilt unit. As much as I would like to learn how to pull one apart and rebuild it. It's not worth the possibility of messing one of these up or having an unreliable starter.

    Another note, I got the port motor tilted up and it's soaking now, hopefully I'll have it freed up by this weekend.
  • Little_GeneLittle_Gene Posts: 371 Deckhand
    So I went out and played with the port motor a bit last night. I can turn it back and forth about a 1/4" before it locks solid. funny thing is the noise it makes when it locks up is coming from the foot. Got to looking at the parts blowup on brownspoint last night, and it looks like there was a quick flush fitting. Now below the cavitation plate there are two screws on the starboard motor, on the port motor there is a screw and what looks like a sleeve sticking out to the side where the second screw would be. Am I correct in thinking these are where you fill/check the foot oil? And how bad would it be if someone drained the oil, and then left it exposed for 12-14 years or so?

    :banghead Wanting to really throttle my uncle right now.
  • capt louiecapt louie citrus countyPosts: 9,962 Moderator
    Does the "sleeve" thread out ? It may be part of the filler was left on it ?
    "You'll get your weather"
  • Jim311Jim311 Posts: 4,929 Captain
    I'm thinking you've got one of two problems. One, something in the powerhead is seriously broken, like a snapped connecting rod or broken piston. Two, something in the lower unit is locked up. Make sure the lower unit is shifted into neutral. If the motor free spins after that then it could be a blown up lower unit.
  • APEAPE Posts: 973 Officer
    Gene it sounds like the lower unit is in gear, this could of been done while messing with the throttle shifter or during a halfazz water pump replacement job that your uncle started 15 years ago? I have a below the deck boat fuel tank that I don't need if you need a tank to hook up to test your engines and you can keep it because its just in the way.
  • Landlocked_Landlocked_ Posts: 590 Officer
    Gene I also have a 6 gallon portable tank I could spare. Been sitting around for ages, a thorough cleaning would be a must. If you're interested give me a text or call and I'll bring one with me tomorrow. PM sent with contact info
  • cprcpr Posts: 9,309 Admiral
    you my also want to try this now that it fires

    dunk's decarbon

    This works for Carbed, EFI, Ficht, HPDI, Optimax and even 4 strokes...
    First you need a separate small fuel tank. One of those 3 gal red Tempos works great or an empty gal milk jug will also work, but might be a bit messier..

    I use Seafoam over the OEM stuff like OMC Engine Tuner or Merc Power Tune because in the last few years they changed the formula and you have to let them sit up 12 hours. Who's got time for that?? Seafoam you can buy from NAPA, CarQuest or other auto stores. Seafoam works in 15 mins.

    You'll need 3/4 gal of gasoline and one 16oz can of seafoam for each engine. Don't forget to add 3oz of oil if you are premixing in a carbed engine. Use about 3 ft piece of fuel hose off the little tank. You connect this tank to your engine by pulling off the main tank fuel hose off the intake side of your water separating fuel filter and plug the hose off the small tank on to that fitting. Or you can separate the fuel line on the tank side primer ball, so you can still use your primer. If you have an engine that has fuel plug then you need a fuel plug on the little tanks hose.

    Start the engine, let it warm up and start pulling the mix into the engine. You may have to increase the idle to keep it running once she get loaded with the Seafoam. Run the engine 15 mins in the dock or just cruising around under 2500. Then shut it down and let it sit for 15 mins. Restart the engine, the smoke you see is the carbon burning off. Do the whole thing again and let her sit again for 15 mins. If she smokes after the second time do it again, but I've never seen one still smoke after three doses. The gallon mix should be enough to do this 3 times. You don't need any wide open throttle, you don't need to change the plugs. If it's cleaning the combustion chambers it's also cleaning the plugs, but every 50-60hrs is good time to change plugs in most engines.

    I cleaned a antique evinrude one time that had a 1/4" of solid carbon on the exhaust chamber walls by running a 1/2 gal of the mix through it. Seafoam has been around since the 30's and it's what they used when they were burning straight 4 stroke 40SAE oils in outboards.

    You guys with the 4 strokes think you are immune from this? Those engines work 10 times as hard as any auto engine ever will and they will carbon up. I bought a Bronco two years ago that had 95,000 miles on it. When I used seafoam on it I had the neighbors hanging out of their front doors looking for where the fire was after I started it the first time there so much smoke.

    Too many are under the assumption that it's totally the 2 stroke oil that causes the carbon, Wrong... it's also the additives they put in the fuels today. The carbon inhibitors in 2 stroke oil are there for this reason also. Remember when gasoline used to smell like gasoline, today it smells more like bad cologne.

    For those guys that like to do the carbon treatment by spraying it down the carbs Seafoam also comes in spray can called Deep Creep. It's the same stuff under pressure. Says right on the can Oxygen Sensor Safe, for you Yam guys.

    After that if your engine maunf recommends a daily additive treatment then do that in the mean time, but all 2 stroke outboard need decarboned every 50-60hrs. If I owned a 4 stroke I would do it the same. Once you are set up with the tank and hose the Seafoam is only 5-6 bucks can. It to easy not to do it
    "The test of a first-rate intelligence is the ability to hold two opposed ideas in the mind at the same time, and still retain the ability to function." F. Scott Fitzgerald

    "Prediction is very difficult, especially if it's about the future." Niels Bohr
  • Little_GeneLittle_Gene Posts: 371 Deckhand
    Landlocked got me a tank at the bash, and after pressure washing the hell out of it Sunday It looks like it's ready for use. My question is this, is there a specific 2 stroke oil to use with boats or will any synthetic 2s oil work? what do you guys think I should mix it at till I'm sure the oil injection is working?
  • Jim311Jim311 Posts: 4,929 Captain
    50:1 and any TCW3 two stroke oil should do the jog.
  • Little_GeneLittle_Gene Posts: 371 Deckhand
    Thanks Jim!
  • BillyBilly ChassahowitzkaPosts: 2,705 Captain
    Jim311 wrote: »
    50:1 and any TCW3 two stroke oil should do the jog.

    Yep....what Jim said.

    Watch the injection tank to see if it is going down, mark it with pencil, and once you are confident the injection system is working you are good to go.

    Keep in mind though it takes awhile to use enough oil to see if the system is working as it uses different amounts depending on load. You idle around a bunch and it "ain't" going to move much as the injection system usually drops down to around 100:1 when there isn't a load on the motor.

    "And the ocean is howling for the things that might have been..."
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