2003 Tohatsu 9.8B 2 Stroke ran good now wont start

[Sea Rider]

Gee bad news, a crime to tear a whole block just to have a look inside.

It's Mission Impossible to suspected water intrussion inside engine through exhaust port gaskets because in the event water was leaking inside engine while working the excessive heat found there will evaporate water droplets through the exhaust. It's the exhaust not the intake port. Is not the same water entering crankcase through intake port gasket, this engine happens to have a closed intake port, no lid, no gasket so this suspected water intrussion issue does not apply.

The rubber hoses mentioned earlier are lubrication pipes that drives fuel/iol mixture to crankcase's bearings and impossible to be clogged, unless you're running 5 :1 fuel rates and engine smoking worts that a squad of chinese smokers at a poker club. If clogged, that engine will be dead moons back and engine jammed due to extremely poor lubrication.

That's why like having electrical spare parts available, swap and test and send to hell dealers who love to make huge profits. What do you plan doing next. It's very difficult to address the problem directly on line, how about nice pics of your exhaust port and cylinder head to check your overall engine cond, and go from there.

Happy Boating

 

[panamakid]

How much resistance should I have when pulling the cord or turning the flywheel by hand (with plugs in)?

I have never had a outboard this small. The compression numbers are good but when you pull the cord it is pretty easy.

Here is a video of about 10 days ago when the motor was running.

https://www.youtube.com/watch?v=ZfeT1so3f_A

Please note: I greased the pull start assembly and it no longer slips when pull starting.

I will try and make another video of the motor now, doing a compression test, showing spark, and a general walk through of block.

 

[Bosunsmate]

Bosunsmate,

I have not checked the bypass hoses yet. I did ask the dealer to do it and shared the wet crank case theory.

I will do it today.

I will say that the motor has less "Bounce Back" than another 10 HP I pulled on. Mine is "smoother"

As if a compression valve is stuck open. I know this is a 2 stroke so that rules that out.



I have only done a timing test on a car, one clamp went on the plug wire the other on the battery.

This Motor has no battery so where does the clamp go?

Those hoses will likely be clogged if you have had water intrusion, the water fuel emulsification gets stuck in those check valves that you can see on the parts diagram you provided. so when you blow suck down them to check they are clear they are clogged up.

You use a stand alone battery. Pull your car up alongside and you can use that

 

[Bosunsmate]

How much resistance should I have when pulling the cord or turning the flywheel by hand (with plugs in)?

I have never had a outboard this small. The compression numbers are good but when you pull the cord it is pretty easy.

.

It should be what it was before you had this problem

 

[Bosunsmate]

The Spark Plugs are totally black thick with oil/carbon gunk the texture of old axle grease, beyond fouled.

.

Dont forget this that you found, that stuff would block any check valve so the question is what caused it, i say its water mixed with oil and fuel

 

[panamakid]

I checked the hoses, they all are ok by either blowing air through or sucking air out.

https://plus.google.com/u/0/photos/1...81662232057873

Album of motor,

Here is the video of compression test and spark

https://www.youtube.com/watch?v=l0D1mfTKTPc

 

[panamakid]

[No message]

 

[Bosunsmate]

Well compressions good and spark so looks like its up to checking timing
Im just heading away on holiday for a couple of days but keep at it, a motor with that good compression is a keeper

 

[Sea Rider]

If engine was running strong before dropped dead your timing is good, If dealer was about to tear crankcase in halves, why don't you remove head and check head gasket, cylinder walls, piston condition. Could take advantage to de carbon piston head, inner head. Will need new head gasket along base gasket when reassembling. Could check thermo cond as well once head is removed. Is small filter located before fuel pump clean, that's unobstructed with good fuel flow. Is your fuel/oil rate 50:1 ?

Happy Boating

 

[panamakid]

Can a rookie with no major tools rebuild this thing? I have worked on dirt bikes and stuff.

If I crack it open and nothing breaks and find out I need a rebuild I found kits is $266 for everything.

I just need to tell them what size rings and piston . Then I figure $100 to have it honed/machined if it needs it, and then put it all back together.

So like $400 in parts, shipping, and machining. That is only if it needs a rebuild, may just need a cleaning or something.

How many hours do small engines like this take to rebuild?

 

[Sea Rider]

Panamakid,

You won't have an idea of what you neeed to do to engine untill head is removed, If cylinder walls have issues, scratches, are deformed will need to have that block sent to a machine shop and have both cylinders honed, will need to buy 2 piston/o'ring 0.5 mm sets to match the honed work. But that's pure speculation.

How much time need to reassemble a complete block, will depend entirely on how skilled you are, it's not rocket science, if you have deal with 2 strokes motorcycles assume it's the same if motorcycles have 2 parted blocks as outboards.

Best scenario, Head gasket, lower gasket, thermo, thermo gasket if having one + hand labor. No need special tools, just a torquemeter to torque head back to fact specs.

Worst scenario : 2 pistons, 2 ring 0.5 mm sets, head gasket, lower gasket, thermo if in bad shape, machine shop work, hand labor.

Happy Boating

 

[panamakid]

"Best scenario, Head gasket, lower gasket, thermo, thermo gasket if having one + hand labor. No need special tools, just a torquemeter to torque head back to fact specs."

If I did the above mentioned Head gasket, lower gasket, thermo would that possibly fix the problem?



It seems like I am ether not getting spark when the plugs are in the cylinder or at the right time TDC.


Could compression be ok, yet still have a cylinder or piston ring out of specs enough to not allow the engine to start?

It seems like if I have a stuck ring or something It would either start and run poorly or not have good compression.




I have torque wrench, complete huge craftsman tool kit.

http://www.maxrules.com have entire rebuild kits for $266

NISSAN TOHATSU Rebuild kits include all of the following items, as required, unless noted:

• PISTONS/ RINGS/ WRISTPINS/ RETAINERS
• COMPLETE GASKET & SEAL KIT
• CRANKSHAFT UPPER AND LOWER MAIN BEARINGS
• WRIST PIN BEARINGS
• THERMOSTAT (if present) AND IMPELLER
• GASKET SEALING COMPOUNDS AND CRANKCASE SEALER
• EXPLODED VIEWS, ASSEMBLY AND TORQUE SPECS
• TECHNICAL ASSISTANCE FROM THE MASTERTECH

So worst case $266 + machine shop fees. Plus time. If it can be done in a weekend I am in.

If this is going to consume me for a week+ then I am not sure I can do it.

I have limited work space.


"Best scenario, Head gasket, lower gasket, thermo, thermo gasket if having one + hand labor. No need special tools, just a torquemeter to torque head back to fact specs."


Head Gasket, Thermo, bottom gasket = $57.00.


How many hours could you do the work in? Lets say if you are a 10, then I am a 5.5.. Or if you could do it in 4 hours than I need 9ish (just a guess).

I am perfectly capable of turning bolts, But it is hard to predict if something will break off.

I am willing to invest a few hundred dollars and a 2-3 days (4-5 hrs per day).

 

[Sea Rider]

To start with, you must be 100% sure you have good sparks on both plugs. Ground spark plugs and at a dark place like a garage, pull cord and check if both sparks are visible, healthy and blue. Can't speak for all head gaskets, did occur to me and to some other boaters as well, engine dropped dead at speed when engines were working spot on throughout the whole throttle range. How many times have you started that engine from day one you bough it ? ran good, right ? If so, timing advance and carb sync are ok. Useless playing with them as could be turned "out of sync".

Once block is split open, will need to clean well both mating surfaces, along head mating surfaces, must remove all gasket leftovers, decarbon inner head and piston head and clean all water paths from block and cylinder head. That could take its time as all mating surfaces must be near shinny and even, the rest is just assembly work. When you send a block to a machine shop must know the factory tolerances. If cylinder are in pristine cond could take advantege to install a new standard o'ring kit. If deformed, with scratches block must be passsed to next 0.5 mm piston/ring set. Cylinder walls must be measured with special tooling.

If all electrical, fuel related issues are spot on, would go straight and pull head from block, most boaters here have issues pulling heads to check or replace worn, dried, hardened gaskets, it's a preventive maintenance, once is kaput, becomes a corrective maintenance. When outboards begins to use coolant as in cars, changing head gaskets will pass to history, meanwhile is a must change item from time to time. You could break any bolt when removing them specially if seized by salt due to poor rinsing after use or no rinsing at all.

If having a blown head gasket, don't expect to find a big hole or a huge internal blast issue, replacing a faulty gasket will spring back to life a dead engine. Take your time, being in a hurry is no good...

Happy Boating

 

[Bosunsmate]

You can hear your compression is sufficient when you release the valve on that video. Too start an engine out of the water with no back pressure requires hardly any compression, what you have there is more than enough.
You said you have good spark before. If you arent sure what good spark is test it with a spark tester set too 7/16 gap. Spark tester costs $5 or make one yourself.
Timing can go out at anytime if for example the powerpack develops a fault which is why most engine manufacturers recommend one be carried as a spare on board.

 

[Bosunsmate]

"

It seems like if I have a stuck ring or something It would either start and run poorly or not have good compression.

No as it would run on the other cylinder

 

[Sea Rider]

Timing can go out at anytime if for example the powerpack develops a fault which is why most engine manufacturers recommend one be carried as a spare on board.

Sorry, you can't have out of tming CD issue on 2 stroke engines, as it's a mechanical timing and carb synchro related issue, unless mechanically playing with stated synchro and desinchronizing the whole engine. CD/Timing Advance/ Carb, are the 3 Musqueteers. Haven't seen stated on any owner's manual you must carry a spare CD, for some peace of mind, you should carry a spark plug set and a spare prop though..

If both sparks are healthy and strong after testing with gap tester > Tear Cylinder Head > Anyway, pulling head off is the first thing a dealer should do before tearing complete block down.

Happy Boating

 

[panamakid]

I spoke with another mechanic this weekend. He also did not want to work on my motor as he was fixing 300HP motors.

He said that it is possible I do not have spark under compression. Is there a way I can test this?

I see new CDI packs are $300!!!

Also my brother told me that when he used the boat a few weeks back he would get shocked when touching the cowling release lever. He also said that it ran better with no cowling like it was grounding out on the metal cowling bracket.

He said he cleaned the spark plug cap and applied spark plug grease and it stopped shocking him and ran better.

Could this have fried the coil/cdi?

When doing gap or visual I get bright spark. I can not confirm blue though.

See end of my video
2003 Tohatsu M9.8B 2 Stroke - YouTube
https://www.youtube.com

 

[Sea Rider]

Cleaning and applying grease won't do much good in the short term. You seem to have cracked end caps and electricity shorting to ground, even plug cable doing same if hardened or cracked. You could replace both end caps, can buy them separately, It's a unscrew old ones and screw new ones onto cable.

After you replace both, wrap both cables with several rounds of 3M electric tape, starting end cap and going towards CD/IC small cap. Cheapper than buying the whole unit. The CD/IC unit is still working, probably not delivering full electricity to ignite fuel on combustion chamber, electricity leak issues. Tohatsu fires 2 sparks per revolution...

Happy Boating

 

[Bosunsmate]

Sorry, you can't have out of tming CD issue on 2 stroke engines, as it's a mechanical timing and carb synchro related issue,

Happy Boating

Incorrect, when the powerpacks go the electronics inside them, capacitors etc malfunction and send the fire signal out at erratic times. Ive seen it many times.

 

[Bosunsmate]

I spoke with another mechanic this weekend. He also did not want to work on my motor as he was fixing 300HP motors.

He said that it is possible I do not have spark under compression. Is there a way I can test this?

I see new CDI packs are $300!!!

Also my brother told me that when he used the boat a few weeks back he would get shocked when touching the cowling release lever. He also said that it ran better with no cowling like it was grounding out on the metal cowling bracket.

He said he cleaned the spark plug cap and applied spark plug grease and it stopped shocking him and ran better.

Could this have fried the coil/cdi?

When doing gap or visual I get bright spark. I can not confirm blue though.

See end of my video
2003 Tohatsu M9.8B 2 Stroke - YouTube
https://www.youtube.com

Run it at night if you want to see if its shorting, you are also trying to run it without having the cowling connected and its still not running.

If its jumping a 7/16 gap then dont get hung up on whether its blue or not. You need a timing light to check the rest of the electronics