Tohatsu 18HP 4stroke 2005

[Michael Bryson]

I want to service/change my impeller and lower unit oil on my 18hp 4 stroke 2005 tohatsu. can I find a manual free online or any advice on this? I have done it on my larger outboard years ago but I need a little refresher. im rusty. lol

thank you, Michael

 

[Sea Rider]

Re: Tohatsu 18HP 4stroke 2005

Just remove 4 lower bolts and upper spring pin that secures shift rods onto joint tube. LU should drop if driveshaft is not seized to crankshaft.

Happy Boating

 

[pvanv]

Re: Tohatsu 18HP 4stroke 2005

Specify your precise model/serial, not year. The Factory service manual is copyrighted, so is not available for free DL. See any Tohatsu/Nissan dealer for a Factory service manual. Install a complete wp kit, not just the impeller. You will also want a new oil filter. Run non-synthetic 10w-30 FC-W oil; don't overfill. Be careful you don'y lose the aluminum gasket under the head of the oil drain plug. Consider changing the LU lube at the same time.

 

[Michael Bryson]

Re: Tohatsu 18HP 4stroke 2005

Specify your precise model/serial, not year. The Factory service manual is copyrighted, so is not available for free DL. See any Tohatsu/Nissan dealer for a Factory service manual. Install a complete wp kit, not just the impeller. You will also want a new oil filter. Run non-synthetic 10w-30 FC-W oil; don't overfill. Be careful you don'y lose the aluminum gasket under the head of the oil drain plug. Consider changing the LU lube at the same time.

Thank you Paul.
serial # is 037757XD
model MFS18 B2

 

[Michael Bryson]

Re: Tohatsu 18HP 4stroke 2005

Paul,

I ordered the impeller, O ring and key way. I had a hard time finding a complete kit and in the past when I've done my big Suzuki all I ever needed was the impeller and O ring. should I purchase any other parts? I and changing the crankcase oil and filter as well as the LU lube. I have new Suzuki LU lube oil left over from a past service. can I use that for the LU? is LU lube all the same?

thank you, MB

 

[Sea Rider]

Re: Tohatsu 18HP 4stroke 2005

Gear oils are usually 80/90 or 90 grade rated, if so can use Susy leftover gear oil.

Happy Boating

 

[pvanv]

Re: Tohatsu 18HP 4stroke 2005

Paul,

I ordered the impeller, O ring and key way. I had a hard time finding a complete kit and in the past when I've done my big Suzuki all I ever needed was the impeller and O ring. should I purchase any other parts? I and changing the crankcase oil and filter as well as the LU lube. I have new Suzuki LU lube oil left over from a past service. can I use that for the LU? is LU lube all the same?

thank you, MB

You have some incorrect information.

The 18B2 does not use any o-ring at all in the water pump system (except below the lower water pump housing, sealing the LU from the pump... that is part of the LU seal kit). I would question whether you are getting the correct parts. Always replace the plate and cup (complete kit) along with the impeller... it costs a few bucks more, but pumps a lot better, lasts longer, and is the same labor cost. Many aftermarket impellers are not as good quality as the Factory parts.

Any Tohatsu/Nissan dealer (including several forum members... even me), can provide you with:
WATER PUMP KIT : 9.9HP ~ 20HP
Water pump repair kit. Includes all parts needed to replace water pump. (cup, bolts, impeller, key, wear plate, gaskets, etc.)
Fits:
9.9/12/15/18hp 2-stroke models
9.9/15/18/20hp 4-stroke models
DOES NOT fit the 9.8hp model
Part # 362873221M
$50.68

Lube for the LU can be any SAE 90 EP gear oil, even multi-viscosity is OK... just don't run type C, which is only for the old OMC electric-shift models.