Thoughts on rebuilding 30 HP Johnson outboard.....

[bulletbob]

 I am not a 2 stroke/outboard guy all that much, but am a  69 YO retired ASE Master technician that made a life with internal combustion engines.. Just this past october I rebuilt the engine in my Grand Cherokee in frame, in the driveway, on my back, new pistons and all, so I have some "residual" ability left from my work years... I  have a tired 1996 Johnson 30 HP 2 stroke.. 90 PSI each cyl... It should have more like 120 psi. It starts[hard], and  still runs pretty strong  at mid and full throttle, but idles poorly and sneezes like crazy at low/idle speed.. Sure signs of low compression.. No rod/piston noise that I can hear.. I am thinking that in this case a set of rings and a cyl honing as well as new crank seals should get the compression up to where this engine runs better.. I am just not in a position to spend $1500 or so on a 20 YO engine that might have 500 hours on  it, and is almost s tired as mine.. I keep buying used engines, and after a year or two of light use, they always seems to go bad.. So I  just want to try and rebuild what I already have,.. Its pretty clean looking, good lower unit, electric start remote steer etc.. Rings and gasket set as well as the factory manual, probably less than around 150-175... Just looking for any thoughts, insight,  helpful advice. "tech support" from those that have done similar, or those that are serious outboard motor guys with more experience than I have.. any suggestions would be well appreciated... bob

[sherman brown]

3 minutes ago, bulletbob said:

 I am not a 2 stroke/outboard guy all that much, but am a  69 YO retired ASE Master technician that made a life with internal combustion engines.. Just this past october I rebuilt the engine in my Grand Cherokee in frame, in the driveway, on my back, new pistons and all, so I have some "residual" ability left from my work years... I  have a tired 1996 Johnson 30 HP 2 stroke.. 90 PSI each cyl... It should have more like 120 psi. It starts[hard], and  still runs pretty strong  at mid and full throttle, but idles poorly and sneezes like crazy at low/idle speed.. Sure signs of low compression.. No rod/piston noise that I can hear.. I am thinking that in this case a set of rings and a cyl honing as well as new crank seals should get the compression up to where this engine runs better.. I am just not in a position to spend $1500 or so on a 20 YO engine that might have 500 hours on  it, and is almost s tired as mine.. I keep buying used engines, and after a year or two of light use, they always seems to go bad.. So I  just want to try and rebuild what I already have,.. Its pretty clean looking, good lower unit, electric start remote steer etc.. Rings and gasket set as well as the factory manual, probably less than around 150-175... Just looking for any thoughts, insight,  helpful advice. "tech support" from those that have done similar, or those that are serious outboard motor guys with more experience than I have.. any suggestions would be well appreciated... bob

I can't really give you any advice because it sounds like you already have everything you need, knowledge. All the old 2 stroke motors are pretty much the same and are straightforward. for someone who has the knowledge to rebuild auto engines shouldn't have any problem rebuilding any 2-stroke boat motor. the only thing is to be sure and torque the head bolts as the instructions say they should be torqued. the rest is so simple you should have no problem. all the old 2-stroke motors I have dealt with have roller bearings so no need to check the clearance like an auto motor. they also use reed valves so you don't have to set the valves. now all the rest is simple. and rebuilding your motor will be the same as a new motor. but you may need to adjust the old cards or rebuild them.

[rolmops]

I would start with decarbing the engine, then pour some steering fluid or better, magical mystery oil into the cylinders and let it sit overnight. This will loosen up sticky rings. Now let it run until it is warm and then do a compression test again It may well be that the compression has gone up quite a bit. If not, go ahead and do a complete rebuild with the help of a factory manual (not some Clymer or Seloc). Go oversize if you have to, or if you really want to, go perfect go for a resleeve.

Edited February 11 by rolmops

[bulletbob]

 I have done the decarb,  cyl soak, "free the rings" deal.. Thats not the problem...  At 90 PSI  on both cyls, its  just worn, I have known it for several years.. Plus I overheated it last year when the water pump failed and melted into a big rubber blob,, I blew the head gasket, replaced it and the pump, and it did run afterwards, but the  "tiredness" was even  more pronounced.. Its just time.. I really don't think it needs more than a hone, rings and new crank seals, as the bores looked pretty decent last year when I had the head off.. I have had several of these 2 cyl OMC  2 strokes, and from my experience, they want 120 PSI or more  to run  really well.. Once they get below 100 psi, they start hard, stall when cold, and sneeze like hell at low speed... Others may have had better experience, but I have owned 2 30's, as well as a 28SPL, and they stated getting balky as the compression dropped below a certain point...  I would buy a clean used one, but guys are asking $1200-$1500 for 25 YO 25 or 30 HP OMC 2 strokes, and  i have not had much luck with OB engines at that age.. I buy one for a grand or close, and  a year or two  later its    pretty much at lifes end... Most guys sell OB engines when they start getting tired and unreliable.. Not much need to  dump a good running dependable OB  motor for most  boaters.. Not going to trust another old motor, this time  maybe I will  simply try rebuilding it myself ..bob

[rolmops]

This may sound weird, but may I suggest that the next block you buy is a 1970s or 80s.

What happened is that OEM constantly tried to squeeze more horse power out of the same block size. In the late fiftees there was the 30 and 35 hp block. These were very sturdy solid blocks for their range. As time went on using the same basic block , they went to forty, fifty and in the end even 55 horse engines all based on the same size block. Obviously, the more you squeeze out of a block, the harder they work and the worse they wear. In my experience the late seventies and early  eighties pre1985 and preVRO is where the best blocks are found. I still have 2 very good 1957 35 horse Seahorses that I never had to work on apart from regular maintenance. I think that they have well over 3000 hours each.

I would choose not to hone but to go oversize. Honing might actually bring the compression down even more. Having a good machine shop do the work might cost quite a bit but it will get you a new block

If you know how to rebuild a jeep in your driveway, you should not have any problems with a 2 stroke on the work bench in your garage.

Until you have time to do such a rebuild you may want to run the engine on a 1-32 mix , it tends to bring the compression up just a little.

Edited February 12 by rolmops

[bulletbob]

Prices are nuts.. $250 to bore the block, pistons are about $175 each with rings, and thats without a  gasket set which is a couple hundred bucks, unless I get chinese ones... Probably $800 in parts, if I do  everything myself, not including plugs, solvents, gasket sealer, penetrating oil,  expendables such as sandpaper,  etc... No wonder guys are always looking for good used outboards... Might also go with a known good power head... Clean one on ebay with 120 psi each hole.. I can't tell you how many times I have been through this.. I lament each and every good running OB motor I ever sold for way too little money years ago.. Past 3 or 4 motors i have bought have crapped out in a few years of very easy use, and good care... Like I said,  most guys know when its time to get out of a motor, and as they say - "there's an ass for every seat"... bob

[mr 580]

I’m not surprised at what you are finding for costs on parts and materials to rebuild.  Makes it hard to justify even when you can do the labor yourself. Suggest you go to “online outboards.com” and check prices on new 25/30 hp outboards.  My neighbor and I have both bought Suzuki’s from them several years ago without a lick of a problem.  Neighbor replaced a 25hp Merc 2 stroke with a 20hp Suzuki and had better performance.  Wouldn’t be surprised if you could go from a 30hp to a new 25hp with less weight and much better fuel use.  Never hurts to know what new costs.

[bulletbob]

 I could go to a 20 no problem.. Boat is only a 14 root aluminum, although it is a "heavy" aluminum boat.. Remote steer with side console.. Only motors I can find are typically 30 HP long shaft with remote steer.. a 20 or 25  is better suited, but they are TOUGH to find in remote steer/electric start and when you do find a clean used one, sellers know they are pretty rare, and want a fortune.. A clean 50 or 70 2 stroke is cheaper than a clean 20 or 25 remote steer long shaft... Anyway, not sure what I am going to do..  I might just buy a  9.9 or 15 HP tiller, forget about the side console for now, until I can find a reasonably priced 25 remote somewhere,. Prices are just  really crazy new . used  parts, labor , everything..  I was at a boat dealer the other day looking for parts, $200 an hour for labor, but hey ONLY $179.95 an hour for friends and family!.. What a deal!.. Right there on a big sign.. This was in  Sayre Pa...

 

  When I rebuilt my Grand Cherokee engine in Oct. -

$150 to check the head, make sure it had no cracks

 $150 to plane  the head..

  $150 to press 6 new pistons onto the old connecting rods..

 

 So $450 for what is NOT  much labor if you know what these procedures entail.. This is about 1 1/2 hours labor at most.

 I had to resurface the valves, install new valve seals myself.. That would have been another $300-400 or so.. A  factory rebuilt head  was only $400.... Its just the way things are now, labor is even worse than parts.. Soon no one will be able to afford fixing anything, and will be forced to buy new... bob

 

Edited February 13 by bulletbob

[rolmops]

5 hours ago, mr 580 said:

I’m not surprised at what you are finding for costs on parts and materials to rebuild.  Makes it hard to justify even when you can do the labor yourself. Suggest you go to “online outboards.com” and check prices on new 25/30 hp outboards.  My neighbor and I have both bought Suzuki’s from them several years ago without a lick of a problem.  Neighbor replaced a 25hp Merc 2 stroke with a 20hp Suzuki and had better performance.  Wouldn’t be surprised if you could go from a 30hp to a new 25hp with less weight and much better fuel use.  Never hurts to know what new costs.

I also bought a Suzuki from online outboards for all the reasons you mentioned. Part of my calculation for doing this is also getting older and while not less agile just yet. I certainly will be a few years from now. At the ripe old age of 73 I do not want to waste my time fixing things when what I really want to do is floating and daydreaming on the water. The 9.9 I bought is top of the line with an extra long shaft and T&T. I love just looking at it, let alone motoring with it. It's pure unadulterated luxury. I did not even mention the 5 year warranty and the almost silence on the water when the engine runs. (Admittedly I am a bit deaf) I added a little servo and actuator hooked it into a trollmaster3 system and now I can be away from the wheel and steer and control speed everywhere in the boat with my wireless little gizmo hanging from my neck

As for the 20 horse. It is the same block as the 9.9 and going that way may mean falling in the same trap of pushing the little motor too hard and creating the same trouble of early wear and tear,which you are dealing with now.

Edited February 13 by rolmops

[mr 580]

I’ve put a lot of hours on small Hondas, Yamahas, and Suzuki in the last 20 years.  I put one water pump and a set of plugs in a 10 year old Yamaha because I felt bad I hadn’t done anything to it.  A new 20 hp Suzuki long shaft with controls looks to be under $3200 w/ frt (not sure on tax).  5 year warranty and build in rev limiter.  I change engine oil and lower unit oil which is really simple.  I’d rather fish than tinker with an old motor.  Don’t look for labor rates to go down as the number of technicians is limited across the board-auto, ag, construction, marine and trucks.  Every shop is looking.

[bulletbob]

 I don't mind tinkering at all.. Its what I do... i do understand  what you guys are saying however. Right now, can't see swinging 3K + even though thats a good price for a 20 HP 4 stroke  with controls.. Another really odd thing I have found is this- Its often cheaper to buy an entire boat/motor trailer than just the engine...  i have seen a LOT of guys buy an entire rig and then sell or just give away the boat... I have seen some some pretty good deals at times, and usually when the motor is on the boat you can hear it run... I am keeping my eyes open at this time as I decide which way to go.. Another option is this-

 Buy cheap entire gasket set on ebay/amazon for REAL cheap, like 30 bucks... Buy rings same place. around $ 70-80 for both pistons.... Now at around $125 or less, I can  Hone/ re ring/ reseal the engine real cheap and hope for the best.. I have had pretty decent luck with cheap ebay parts on all my cars/mowers/chain saws/ outboards etc.. Just last year i used a Chinese head gasket on this 30 HP, and it was fine, looked 100% OEM to me.. been using ebay wheel bearings/brakes/engine parts/starters/alternators for many years, and  they have lasted as long as anything I even bought at NAPA/Autozone/Advance at about 1/3 to 1/2 the price...  So I dunno, cheaping out  big time and hoping for the best is another possibility....  anyway, its been an interesting discussion, and I'll post more about what I do if anyone cares to read it..... bob

[rolmops]

2 hours ago, mr 580 said:

I’m not surprised at what you are finding for costs on parts and materials to rebuild.  Makes it hard to justify even when you can do the labor yourself. Suggest you go to “online outboards.com” and check prices on new 25/30 hp outboards.  My neighbor and I have both bought Suzuki’s from them several years ago without a lick of a problem.  Neighbor replaced a 25hp Merc 2 stroke with a 20hp Suzuki and had better performance.  Wouldn’t be surprised if you could go from a 30hp to a new 25hp with less weight and much better fuel use.  Never hurts to know what new costs.