Please help, 2 stroke NS18 problems

[R3zrunn3n]

Probably all the trouble is related to using a non Tohatsu fuel tank. I use a 3.3 Gal Tohatsu fuel tank with a 18 HP and can go boating for hours at 3/4 throttle. For extended boating usually carry 2-1 Gal containers, just in case...

Happy Boating

dude, thanks again for helping with the model #.. it seems the NS18-E2 or the M18-E2 is the same thing and parts all match my motor which has been SOOOOOOOOO helpful in locating parts. Really thank you for that, it's been driving me up the wall the past 2 years.

Question, yesterday I chipped a tiny tiny tiny piece from the small jet where the flat head part is on top, ill try to take a picture of it today.. is it a "big deal", or as long as the jet holes are fine, i'm good?

this gas tank thing is driving me nuts -_-

 

[pvanv]

Keep in mind that you are seeing symptoms of either fuel starvation or overheating electronics. A better tank and hose may fix it. Maybe not.

 

[R3zrunn3n]

Keep in mind that you are seeing symptoms of either fuel starvation or overheating electronics. A better tank and hose may fix it. Maybe not.

thanks man - yesterday I received a new Attwood tank (same one that can have pressure issues.. I was thinking to drill a tiny hold in the cap piece that's "under" the main cap piece, if that makes sense to help with pressure/venting.. if that doesn't work.. what do most ppl do to address the gas venting? install one on the top part of the tank?

 

[pvanv]

First see if there is a malfunction. Unlock the cap a half turn to vent. If that fixes it, you have a bad cap, and can either replace it or modify it as needed.

 

[Sea Rider]

As long as the broken upper part of the jet will let you remove it, it's OK using it that way. Yep, both NS and M 18 versions are same OB. Just curious, why buy a second Altwood tank and not an original OEM one which should be available without the pressure relief system found on newer fuel tanks.

To discard having fuel related restrictions, turn cap half turn out as suggested by Paul, disconnect carb's hose from fuel filter, place a container. With bulb's arrow pointing upwards prime bulb several times and check if the fuel flow is smooth with no restriction or hesitation whatsoever. Filter inside tank and fuel filter must be immaculate clean to achieve that cond.

Before going any further troubleshooting the electrical system, need to have the fuel system working spot on. Report your findings...

Happy Boating

 

[R3zrunn3n]

As long as the broken upper part of the jet will let you remove it, it's OK using it that way. Yep, both NS and M 18 versions are same OB. Just curious, why buy a second Altwood tank and not an original OEM one which should be available without the pressure relief system found on newer fuel tanks.

To discard having fuel related restrictions, turn cap half turn out as suggested by Paul, disconnect carb's hose from fuel filter, place a container. With bulb's arrow pointing upwards prime bulb several times and check if the fuel flow is smooth with no restriction or hesitation whatsoever. Filter inside tank and fuel filter must be immaculate clean to achieve that cond.

Before going any further troubleshooting the electrical system, need to have the fuel system working spot on. Report your findings...

Happy Boating

Sea Rider Real annoying answer actually man, I have exactly 20" between the transom support beams on my boat, the attwood is exactly 20" and is 6 gallons. If I do the OEM 6.6 gallon, it's 22".. it won't fit :facepalm:

I saw those 5-8$ gas tank vents - probably just buyone, drill a hole, install, seal. But definitely do what you said and thanks for that advice, i'll give that a try today when I get home and report back. Just cleaned the fuel filter yesterday..

Another big problem I found last night.. my lower unit? IS ABSOLUTELY LOCKED TIGHT! I cannot get it to come off, took off all 4 bolts/& PIN, and tried everything I could w/ my buddy and we couldn't get it... one thing after another
:frown::frown:

 

[Sea Rider]

A pity that you're experiencing such bad bummers in a row with that nice 18 OB. If you have removed the lower 4 bolts and pulled out the locking pin, the OB has the drive shaft seized against the lower crankshaft which is quite normal once the grease on top of the drive shaft has dried and hardened over time.

Try to separe the lower leg from middle leg banging gently with a hard rubber mallet at both middle sides of the AV plate, once with a small clearance insert 2 wooden/plastic wedges and make their way in banging constantly till the lower leg is dropped. Clean the shaft's splines with Acrylic Thinner, Carb Cleaner, once dry apply a light coat of marine grease, assemble back after whatever work was done on the lower tail.

Prime the fuel bulb as suggested to check the fuel flow, be aware than running any OB on muffs, barrel at idle without load is not same as when running under load throughout the whole throttle range. If with existing fuel or electrical related issues, OB will miss hard when under load at speed...

Happy Boating

 

[R3zrunn3n]

A pity that you're experiencing such bad bummers in a row with that nice 18 OB. If you have removed the lower 4 bolts and pulled out the locking pin, the OB has the drive shaft seized against the lower crankshaft which is quite normal once the grease on top of the drive shaft has dried and hardened over time.

Try to separe the lower leg from middle leg banging gently with a hard rubber mallet at both middle sides of the AV plate, once with a small clearance insert 2 wooden/plastic wedges and make their way in banging constantly till the lower leg is dropped. Clean the shaft's splines with Acrylic Thinner, Carb Cleaner, once dry apply a light coat of marine grease, assemble back after whatever work was done on the lower tail.

Prime the fuel bulb as suggested to check the fuel flow, be aware than running any OB on muffs, barrel at idle without load is not same as when running under load throughout the whole throttle range. If with existing fuel or electrical related issues, OB will miss hard when under load at speed...

Happy Boating

yeah it is a bummer bro. but I won't give up on her, shes clean & I personally think she just needs some TLC and she'll be great for years to come. Plus it's awesome knowledge I'm learning..
I guess i'll keep banging on it, I read somewhere it's not "favorable" and I can create problems if I do that? you know anything about that? I see no other way - some said try using a vehicle jack and put it between the boat and LU.. worth a shot.

Good to know bout the load! had no idea, I didn't know there was too much "electrical" in the motor besides the push to start portion of it.

 

[Sea Rider]

Place a wooden block on top middle AV plate and bang harder on it. Have never used a jack before nor shims as always maintain the upper shaft's splines well greased, the lower leg literally falls down when all related parts that secures them to the middle leg are removed. LOL!!

This is the drive shaft's splines, the ones that seized onto the lower crakshaft...



Paul will certainly know if your case which of both methods works best to use. Assume that want to disassemble the lower leg to have a look at the impeller ? The 2 strokes Tohatsu 18 HP it's my favorite, you'll love that horse when finally runs strong...

The electrical system consists of 3 parts and all work in decrease order, starts at the flywheel with the Exciter Coil which connects to the CD to provide power to the Ignition Coil which produces the spark at the tip of the spark plug. Are simple electric and electronic compact parts compared to oldie engines..

Happy Boating

 

[R3zrunn3n]

I'll have to try that.. I just got done beating the crap out of it and try to put a flathead screwdriver on the tip of the LU but no luck.. does that mean if it's seized up it wont run? or it's seized up enough to just not let the LU off? basically will the rest of my maintenance be okay enough to at least start her up?

I won't give up, but now I think I should probably get the LU Gasket Kit...yeah?

Thanks Sea Rider for your experiece and help
pvanv thanks for all your help!

this LU completely ruined my plan and excitement -_-

 

[pvanv]

When the LU has not been dropped since new, and the grease on the splines is gone, it will get stuck in the crank. The only way I know to disassemble without damage is wedges and patience. Many LU housings have been cracked by pounding on them. Patience, grasshopper.

 

[Sea Rider]

With a seized drive shaft onto the lower crankshaft will be able to run the OB as has been currently running before. If the powerhead or gear box are seized/jammed are 2 different awful scenarios.

The oher way around to free the seized splines will be to remove the entire powerhead from the pan. For that will need to remove 4 bolts located under pan, disconnect 2 kill switch terminals, the fuel hose entering the fuel filter, disconnect the L shaped throttle rod. With left hand grab lower carb, with right hand grab the lower cylinder head portion securely and wiggle vigorously as to lever the powerhead at both mentioned sides. Remove spark plugs to better grab and hold the head.

Will need to buy and install a new base gasket as the current one will be found already burnt or broken when the powerhead has been removed.

If still Mission Impossible to drop the lower leg and or remove the entire powerhead and the water pump is peeing strong don't be left stranded on Terra Firme, LOL!! Use the OB and have nice boating fun..

Happy Boating