I swear...

[Sea Rider]

With OB constantly use, will see white lines forming on cylinder head gasket and water droplets leaking in middle gasket metal ring. OB will miss/hesitate when on cold starts. Warming OB more won?t cure the symptom, will just remedy it shortly to miss again when cold. This head breaking symptom is not mentioned on any Service Manual nor is detectable during a compression test. It?s common sense and knowing internally how all related parts works together as a unit.



Second bad news is that small water droplets leaking from gasket water labyrinth will end rusting, seizing head bolts to crankcase which will become hard to remove and even breaking them against internal threads. Crankcase will need to be sent to the solder guru to have broken bolts carefully removed from crankcase.



Crankcase and cylinder head mating surfaces were filed to smooth cond to seal spot on along new head gasket torqued to factory specs. All internal water passages were soaked with vinegar or W40 for a while, then scrapped off with a sushi wooden stick to remove most traces of salt & oxidation inside.



All water orifices were sprayed with pure vinegar, W40 or carb cleaner depending on the condition found and poked with wooden sushi cotton swaps of different calibers to match different orifice diameters.

Although thermo was serviced before at first 300 worked hours from new, was found bit salty and rusty (1) was soaked in pure vinegar for one hour and a half, dried and polished with an old toothbrush and regular toothpaste, looks mint and works as brand new (2).



Carb & Fuel Lines.-
Although carb was working fine, was disassembled in pieces, upper and lower bodies soaked in hot water for 15 minutes and flushed afterwords with an overdose of generic carb spray. After assembly a carb/timing advance sync was mandatory to make. Running carb bowl dry after use, is a big plus keeping carb interior immaculate clean.



Fuel pump, was not disassembled as internal diaphragm won?t fit or sit nicely again on its original resting position due to E8 deformation. Tank to carb fuel lines were purged with fresh fuel.

Final Assembly.-
Installed new base gasket, greased drive shaft upper splines, sat powerhead and torqued lower bolts tight to pan.

Electrical Components.-
Electrical connectors, bullet connectors and all component grounds have been cleaned and polished to a shinny condition.

All small, medium and large bolts have been removed, threads cleaned and assembled lightly greased with OMC Triple Guard, when in need to remove them again, will be breeze to do so.

Before starting OB on muffs and prior sitting thermo on housing, made a 15 minute high pressure water flush direct on thermo orifice and a 15 minute one on discovered exhaust cover flushing port, the amount of water that flows unrestricted through water labyrinth, peeing port and idle relief port made my day.



In 600 worked hours this 18 has consumed 6 spark plug sets, 7 gear oil refills, 1 cylinder head gasket, 1 thermo gasket, 1 base gasket, 1 can of engine tuner/ power guard, 1 carb spray. Carb, fuel pump, lower leg parts, all electrical components are still original. Ain?t that sweet low cost.

Conclusions.-
No matter how long you flush an OB ON while boating on salted waters will alyways accumulate salt layers due to countless heat/cold cycles through continuous use. Deep removal is only possible by rubbing, scrubbing mechanically. Will Salt Away work that deep, who knows, will need to disassemble cylinder head to check, seeing is believing..

Although Engine Tuner, Power Guard sprays didn?t clean combustion and exhaust chambers to perfection as one would imagine while spraying product though carb with OB warmed up, do find that OB regains its lost agility when applied every 50-100 worked hours, a highly recommended product to have it handy.

Products used for restoration : OMC Triple Guard Grease, Automatic Transmisiom Gear Oil, W40, Engine Tuner, Acrylic Thinner.



For a perfect OB restoration It?s not the two weeks spent what counts, for me it?s all about the personal satisfaction of doing an excellent priceless job to maintain my beloved 18 alive while having extreme fun doing it for peanuts cost.-



Happy Boating...

Note : Post starts page 8..

 

[GA_Boater]

:clap2: Looks good, SR. Nice work on the Tohatsu. She's good for another 600 hours or more! :thumb:

 

[Sea Rider]

:clap2: Looks good, SR. Nice work on the Tohatsu. She's good for another 600 hours or more! :thumb:

Thanks Don,

Knowing now what will find on next restoration, next one will be in the next 300 worked hours LOL!!

Happy Boating

 

[foots]

Excellent rebuild! Nice set up too. We use a similar boat (zodiac) as a run-about skiff for crew changes on the Line boat I work on.

 

[Sea Rider]

Transom Angle Modification.-

Taking advantage that my fiberglass techie was available decided to finally modify my transom angle. This is one thing that wanted to do moons back. The transom was not flat even, there was near one centimeter slope between front and rear side which didn't achieve OB to sit at 90?, sat at less or more angle than 90? when trimmed at second or third hole out transom.



Don?t have any issues whatsoever when a transom needs to be raised or chopped down to match a particular OB brand lower leg right where it needs to work spot on.






Before removing the engine, marked the width of the swivel bracket, no need to center OB if removed again as swivel bracket will sit inside middle transom modification.



After a 2 hour sanding work, transom was finally left flat even at ideal 90?.



Now OB will sit further down than before, anticav plate will ride fully parallel to water level, with least water drag, prop will grip much better having a higher water bed to work with bettering riding on choppy, windy, wavy sea cond along impeccable close tight turns at speed. Ain't that beautiful...

Tomarrow will know if OB needs to be trimmed at second or third hole out transom for that to happen.

Happy Boating

 

[Sea Rider]

Bingo..

Although trim was set to third hole out transom did not dialed what wanted, with the angle modification now dials spot on 90?. Combo floating by itself shows cow's logo being parallel to water level, this confirms how well OB sits angled on transom.



On a 50 Km water test off coast, the rib performed wonderfully, although can boat through choppy, windy, wavy water cond with 0 issues, now handles much better these condition. Prop sits further down and prop angle of attack delivers full thrust at less rpm, grips much better. Would say that now this way underpowered OB is getting it's full 18 HP output revving at 5850 wot revs from max 5800 with 2 up as usually lightly loaded.



In my particular case, if going for the Idiotic Rule of Thumb Cast on Concrete, that Anticav Plate (2) must ride even with lower keel/hull OB would simply have present excessive aereaion on straight water courses and worst performance a tight close dime turns. What you need to do for boating perfection is dial OB lower leg at a given height for water flow to skim right under (1) provided that deck is well balanced and boat runs parallel to water level with OB trimmed to 90?. If in need to raise or lower OB, even shim up, chop transom down it's other story...

Happy Boating

 

[Sea Rider]

This is the parameter I like matching when installingTohatsu and rebadged brands as well :



Some concepts to get the idea clear :
Taller water bed (1) produces better prop grip than at, (2) when OB sits at 90? best angle of attack is achieved while combo is at plane, if not, best prop thrust is lost, it's as swimming with hands while fingers are open.

Skeptics would say that there's more lower leg drag when flow passes skimming right under upper plate, wrong, better prop thrust will override this insignificant cond, if you haven't payed attention to lower leg front design, there's a 10 cm tall (green) sharp edge that will cut flow as cheese no matter if passing under upper or over lower plate.

Updating what combo will achieve without pics will be useless & worthless :



Water flow at speed is passing parallel under small upper deflector plate, that's the sweet lower leg/transom height match. Under that cond, will achieve faster hole shot and plane,



flat middle wake with top performance at any water cond, superb close turns at speed along fuel consumption optimization, "provided" that OB revs inside middle to max wot rpm range with factory delivered prop or a maximized one.

Happy Boating

 

[Sea Rider]

Restoration Re Torque Theme.-

As been saying all OB manufactures recommends a re torque with torque wrench after break in period is over or when changing new head gaskets, that's right after 10-15 worked hours has elapsed. Dealer must perform that adjustment when OB is re tuned to him for general inspection, lower tail oil change, grease or whatever needs to be done.

Now a days more boaters are under going DIY first maintenance, so skipping all about re torque. As an illustration, new cylinder head gasket was torqued to 25 NM, after 25 worked hours was found to 23 NM, 2 less. That proves that with heat gaskets cedes, compress the outer part of the gasket. If head gasket is not torqued back expect some water intrusion on combustion chamber specially when OB is cold, crankcase's and cylinder head mating surfaces rust, corrosion premature deterioration along bolt seizure on crankcase's threads.





If too much time has gone by and head thread seizure has occurred, will think that torque is within factory specs, wrong, the seizure is way more locked than the torque applied to head bolt to budge CW a bit, but you didn't know about that, right ?





For me a re torque on all gaskets that deals with water is all about if plan having the least oxidation, corrosion possible on all cooling water paths and their metal mating surfaces as well, and as the Brits says "Long Live the OB"

Bottom Line : Re torque or not to, that tech issue will leave it entirely up to you...

Happy Boating

 

[Chopperbill]

Found this easy and cheap trick how to get rusted bolts/nuts to loosen up.

 

[Sea Rider]

Thanks Chopperbill for sharing, but automotive issues are not same as marine engine issues. An exterior rusted bolt as in the example is easier to unscrew by that method or by simply applying a few drops of brake fluid to penetrate and release faster as opposed to a bolt seized, near welded by rust and salt water as the seizure is found between lower bolt's thread and cylinder head, thermo, or whatever internal threads.

Happy Boating

 

[Sea Rider]

No Re Torque example to take Into Account...

This is a truthful example of what happens when cylinder head gasket is not re torqued soon after break in period ends. As of owner's saying, OB is running good so needs nothing. This boater has not read his Owners'a Manual at all....

This 18 HP (luckily not mine) is a one year oldie with about 40 run hours from new and never flushed with fresh water afterwords while boating on salt waters. Can see paint deterioration (yellow line) salt line formations protruding around cylinder head gasket. On the medium run powerhead will achieve excessive oxidation & rust on both mating surfaces due to salt water leak along gasket's internal cylinder O?rings degradation.



After break in period has ended, you also need to re torque exhaust cover and base gaskets as well, will be surprised on how much they cede and compresses with heat and use. In this particular case was found ? turn off from factory specs. Now OB runs less noisy and smoother than before.

Happy Boating

 

[Sea Rider]

Moons back started having general stains throughout the whole Rib due to boating sometimes on non clean sea water conditions along grease falling from crane while lifting/lowering Rib to/from sea. Tried several cleaning products such as benzine, acrylic thinner, clothing detergent, dish washing products with 0 avail. Discovered this pure gold bottled cleaning product called Cif Creme.

With only one deep application has done marvels to all inflatable tubes, seats and hull as well. Not to believe with own eyes what this cleaning product can do till you see its fantastic end results.



Just wet what you want to clean, apply product liberally on a wet towel, slide it back and forth or in circular motion, this product contains micro polishing particles that gently cleans. Once cleaned parts have been rinsed and dried, Aerospace 303 Protectant which Iboats stocks is the way to go..

A friend after seeing mine tried this product on his Rib which haven't been cleaned in years, his looked excessively stained due to being used heavily as a work boat. 2 bottles and a half day work latter was restored to near mint cond.



As from yesterday the seagull's whiteness matches nicely the Rib?s impeccable clean tubes.




Cif Creme can be purchased at Amazon, price is darn cheap for the deep cleaning and restoring it does. Can even clean your tennis shoes rubber contour with it. LOL!!

Happy Boating

 

[Sea Rider]

700 Hour Update :

You can?t possibly re torque all 8 head bolts with a torque wrench while powerhead sits on middle pan, 2 lower end ones are mission impossible to be reached. On previous powerhead 600 hours restoration all bolts were torqued to 28 NM. As this OB is serviced religiously at each 100 worked hours, decided at 700 hours to pull powerhead out and make the last & final head re torque to 30 NM to all 10 bolts with torque wrench.

Was afraid damaging new powerhead's base gasket changed on previous restoration, to my full content came out complete in one piece due to having it seated slightly greased. Pan's water labyrinth was found in clean working order.



Can have the whole powerhead sitting on a work bench under 5 minutes as the throttle mechanism is simple to release along 2 kill cord switch cables & unscrewing 4 lower pan bolts.



Powerhead?s lower water intakes were found amazingly clean with no salt adhesion whatsoever. Proper fresh water flushing after each outing and deep cleaning job done on last restoration also contributed for this to happen.

Once powerhead was sitting back on pan took advantage to remove thermo from housing which was found 90% clean, soak it in pure vinegar for half an hour and brush it off 100% clean with an old tooth brush. If wanting to remove thermo at any other opportunity, it's a good thing to lightly grease middle and lower rubber seat (*) that way will come out fast with a simple pull.



Flushed by gravity 1 litter of pure vinegar poured with a plastic container throughout thermo housing and exhaust flushing port, let soak for 15 minutes, then flushed all water passages with high water pressure for 15 minutes.



This crazy cleaning procedure will reduce the salt building inside all hidden water passages inside exhaust chamber. OB pees again as when out of the box, hot water passing throughout the powerhead dissipates faster providing a better overall colder working temp when full throttle & high RPM are in demand. It's strange that this nice flushing port is not mentioned as so in Owner's or Service Manuals.

Was beginning to see a thin 2 stroke oil coat on upper middle pan, assumed it was due to old hardened carb?s bowl o?ring, so time to dismantle carb into pieces and have a look. Although Internal carb was found in pristine cond, was flushed with ? carb spray, jets, idle mixture screw and main nozzle were polished with toothpaste to shinny state. All holes were poked clean with extreme thin wooden swabs.



Lower carb fuel entrance and fuel passage to bowl was found excessively crusted with sandy like adheretions. Now cleaned to mint cond. As part of the 700 hour preventive maintenance, both manifold & bowl o?rings, fuel pump diaphragm and gaskets have been replaced for new ones.



One thing that have been doing for some time is polishing carb?s internal bronze valve seat. Can perform this procedure with thin cotton swabs or roll some cotton tight on a toothpick. Just wet tip in water, add an overdose of toothpaste to it and polish gently in circular motion, polish till consecutive cotton swabs or toothpick swabs changes comes out clean.



Although always run carb dry after each outing, the valve seat was found with sediments, now that?s fully polished, needle valve will freely close spot on against internal valve. This procedure avoids valve tip sticking inside seat due to its polished to touch smoothness.



Although internal carb parts are in top visual cond, exterior is not same, looks aged, rusted in many parts. As long carb works flawlessly throughout the entire throttle range will have to live with that no big deal awful cosmetic look.



The middle pan oiling issue was due to a rubber lubrication pipe leak found at the entrance of the intake manifold, problem corrected & solved. Besides carb?s & fuel pump spare parts have added 2 spark plugs and gear case oil change.

Last but not least performed a long CRC Power Tuner decarbon while OB was running ON on muffs and geared and latter going for a wot spin as if stealing the combo to burn out al PT remains. Now OB is in top shape working order for the next 100 fun hours?



Now that know what to expect to find on powerhead interior, will limit full restoration to each 500 worked hours, a thermo clean and water flush to all water passages as described at each 100 hours.

This extensive preventive maintenance is the only way to assure all year round OB trouble free operation along "Long Live my 18 HP-OB" LOL!!

Happy Boating

 

[Sea Rider]

Bingo,

With OB sitting at the sweet lower leg/transom height the only issue left for a correct transom optimization/prop maximization was finding a 8.5 pitch prop to lessen a bit my OB slight over revving with 2 up and bit worse solo boating, that's at full grip running a 8 pitch prop.



A Tohatsu dealer had some left over props for different HP-OB's and most willing to sell them, so being factory discontinued went straight for 2, one as a spare. Took advantage to order a spare 7 pitch for my 5 HP-OB and a 11 pitch for my 30 HP-OB, both factory over propped.

Waiting for a new Hardline hour/tach prior going for a wot test. The idea is to maximize a prop to move 500 KG with 2 up which is my fixed load at max wot rpm range. A 8.5 pitch prop definitely should put me there...

Happy Boating

 

[Sea Rider]

Been having lately lower backache pain due to extensive 40-50 Km back and forth diurnal cruises, it?s due to having to tiller steer near grasping with fingers while seating at a bad position way aft on cushioned seat. The distance is bit short from throttle grip to aft seat for a comfy drive, tried adding different plastic tube diameters to enlarge it, but the grip being cone shaped it?s impossible to match with anything.


Checked the Internet and found a nice HelmsMate fixed 18" tiller extender, it?s well made and robust. After installation, went for a wot spin, found that with a long extender you can only turn to port side, impossible towards starboard as the extender will run towards me. Being useless, ended shortening from 18" to 11" which turns spot on at both sides while throttling back of me.



This extender is intended for trolling purposes only and not advisable for speed boating due to flexing a bit on grip, to solve that issue changed the middle locking mechanism for a 1/2" bolt & nut. Have added a bridle at rear of extender, have released the load on the swivel bracket to 0, now can turn extended grip to both sides much firm and smoother than before at speed.



The rear tube is well built-in to remove and cut to desired shorter size, was wondering how to remove the front cushioned grip. Know that cold makes wonders on anything metal, so placed it overnight on a freezer. Next day the grip slipped out nicely from tube while turning and pulling it out carefully.Now my long distance boating days will be more pleasant and with no lower back pain issues. HelmsMate, you have my Vote.

Happy Boating

 

[Chopperbill]

Have been using that same extension on mine. Solo riding I have to put my body further forward for better weight distribution. I ground down the piece where the lock knob is and use a hose clamp to hold it in place.

 

[Sea Rider]

Luckily don't have to move any weight further to plane fast, can even ride with 2 sitting aft seat and combo will jump on plane near instantly, that's due to having dialed a Tip Top OB/transom match along a excellent prop pitch maximization. These 2 issues will make a day/night boating difference running a very under powered OB.

To ground down means you have filled both protruding plastic pieces that holds locking mechnisms in place to be flat even as rear part, right ?

Happy Boating

 

[Chopperbill]

Yes ground them flat where the tightner knob was. The Suzukis tiller is bigger around than most. Buy the time I get it squeezed on the the tightner hole won't line up anyway.

 

[Sea Rider]

My last Tiny Tach installed on tiller next to grip had its Waterloo Time long ago. A tach is must have item now that the tiller has been extended and cut to fit my boating requirements & comfort. I'm a huge fan of Hardline hour/tachs, are easy to install, can cut wire excess once bolted to tiller and wrapped around spark plug cable.



Hardline tachs are just splash proof, to make them waterproof just add 2 square pieces of tape at lower side of display, now can rinse the OB & tiller without water intrusion on tach.

Installed the tiller extender and guess what, when extended fully down sat flat on top of cushioned seat, clearance between hand and seat was 0. There was too much hand & seat friction going on...





A simple solution was to glue 2 mm hard plastic shims (*) at rear tiller arm, right on the angle that rests against swivel bracket when tiller is fully down.

Incredible how 2 mm shims can rise 1.5" front tiller grip, now hand clearance is excellent and very comfy to tiller drive.



Happy Boating

 

[Sea Rider]

Before OB undergoes a exhaustive 800 hour full maintenance wanted to post the relationship found between combo weight, HP and prop pitch.

Max passengers : 2 souls
Rib/passenger weight
1 Up : 435 Kg
2 Up : 500 Kg
2 Strokes 18 HP/300 CC
Max Wot Range : 5800 rpm
Water cond : slightly choppy.

1 Up & 9 pitch factory delivered prop : 5600 wot rpm.

1 Up & 8 pitch prop without angle modification : 6300 rpm, + 500 more than max stated.

With 8 pitch prop & modified 90? transom angle.

1 Up : 6,160 wot rpm (excellent hole shot) with 1 or 2 up.
2 Up : 6,040 wot rpm (souls sitting aft on rear console seat, less hull drag)




2 Up : 5,920 wot rpm (souls sitting front of each other)

OB is still over revving with 2 up, with 3 up should dial ideal 5800 wot rpm but that won't happen as like boating relatively light with spacious deck. After full maintenance finishes will test with a OEM alum 3 blade 8.5 pitch prop and see which rpm dials ? Definitely way less...

Happy Boating