SailNet Community - Reply to Topic

   Search Sailnet:

 forums  store  


Quick Menu
Forums           
Articles          
Galleries        
Boat Reviews  
Classifieds     
Search SailNet 
Boat Search (new)

Shop the
SailNet Store
Anchor Locker
Boatbuilding & Repair
Charts
Clothing
Electrical
Electronics
Engine
Hatches and Portlights
Interior And Galley
Maintenance
Marine Electronics
Navigation
Other Items
Plumbing and Pumps
Rigging
Safety
Sailing Hardware
Trailer & Watersports
Clearance Items

Advertise Here






Go Back   SailNet Community > On Board > Gear & Maintenance > Engines > Outboard > 9.8HP Tohatsu 2-stroke odd behaviour
 Not a Member? 


Thread: 9.8HP Tohatsu 2-stroke odd behaviour Reply to Thread
Title:
  

By choosing to post the reply below you agree to the rules you agreed to when joining Sailnet.
Click Here to view those rules.

Message:
Trackback:
Send Trackbacks to (Separate multiple URLs with spaces) :
Post Icons
You may choose an icon for your message from the following list:
 

Register Now

In order to be able to post messages on the SailNet Community forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
Please note: After entering 3 characters a list of Usernames already in use will appear and the list will disappear once a valid Username is entered.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Click here to view the posting rules you are bound to when clicking the
'Submit Reply' button below


Additional Options
Miscellaneous Options

Click here to view the posting rules you are bound to when clicking the
'Submit Reply' button below


Topic Review (Newest First)
06-14-2014 10:24 AM
dabnis
Re: 9.8HP Tohatsu 2-stroke odd behaviour

Quote:
Originally Posted by Minnewaska View Post
I'm going to place a nickle bet on the mixture as well.

While it's admittedly a bit of witchcraft and not the same as pulling things apart, I do use this annually. I think it does a reasonably good job of keeping things clean, albeit cheating. You spray the entire can down the air intake, while running. It nearly chokes the motor to a stop, so you let up and then go at it again. Big smoke maker, makes you feel like you are doing something.

Amazon.com: Marine Motor De-Carb 12 oz. aerosol: Sports & Outdoors
I have used this for over 30 years in anything that burns gas, and have not had any fuel related problems, except one time when I forgot to drain the carb on an outboard put away for the winter, my fault. I change the gas, treated with it, once a year in my generator, which runs fine.

Fuel Additives / Treatments | Berryman Products

Paul T
06-14-2014 07:34 AM
Minnewaska
Re: 9.8HP Tohatsu 2-stroke odd behaviour

I'm going to place a nickle bet on the mixture as well.

While it's admittedly a bit of witchcraft and not the same as pulling things apart, I do use this annually. I think it does a reasonably good job of keeping things clean, albeit cheating. You spray the entire can down the air intake, while running. It nearly chokes the motor to a stop, so you let up and then go at it again. Big smoke maker, makes you feel like you are doing something.

Amazon.com: Marine Motor De-Carb 12 oz. aerosol: Sports & Outdoors Amazon.com: Marine Motor De-Carb 12 oz. aerosol: Sports & Outdoors


06-14-2014 06:45 AM
newhaul
Re: 9.8HP Tohatsu 2-stroke odd behaviour

The simple fix it sounds like to me is do what the manufacturer says to do let the engine warm up for a couple min then run at about half throttle under load for about 5 minutes until the engine is fully warmed up. However fresh fuel and new plugs will never hurt an engine either
06-13-2014 09:53 PM
jrd22
Re: 9.8HP Tohatsu 2-stroke odd behaviour

I've had a couple of 9.8 Tohatsu/Nissan 2 strokes and they've generally been the most reliable outboards ever. They can have a problem with old ethanol fuel like a lot of outboards but what you are describing sounds more like a bit of water in the fuel. Try draining the float bowl and fresh fuel. If that doesn't solve the problem take the carb off and disassemble (extremely easy). Soak the parts in carb cleaner and blow out everything with compressed air. That and a new plug has always solved every problem I've ever had with them.
06-13-2014 08:59 PM
dabnis
Re: 9.8HP Tohatsu 2-stroke odd behaviour

Quote:
Originally Posted by Zanshin View Post
I still haven't changed the fuel (I haven't been using the dinghy very much recently), but if it were any of the jets, why does it only happen when I start a cold engine, once it warms up I see no issues at all - good idle, full power, clean and even burn.

But I think I'm getting very close to having to refill the tank with a correcltly measured mixture of oil and fuel, and can then see if the issue resolves itself.
Missed the "cold" part, however I think that a cold engine will not tolerate a lean condition as well as a warm one. Maybe the carb to manifold joint is a bit loose and as the engine warms up the heated metals expand enough to tighten the seal? That is probably a stretch, however. My guess is that there is a lean condition in the high speed system, possibly caused by a small blockage.

You might try running a 50% mix of gas & carb cleaner through it, let it set for a day or two & then give it a good long, hard run with regular mix, fresh fuel.
2 strokes always love new plugs, try the easy things first. Don't ask me how I know that.

Paul T
06-13-2014 07:09 PM
Zanshin
Re: 9.8HP Tohatsu 2-stroke odd behaviour

I still haven't changed the fuel (I haven't been using the dinghy very much recently), but if it were any of the jets, why does it only happen when I start a cold engine, once it warms up I see no issues at all - good idle, full power, clean and even burn.

But I think I'm getting very close to having to refill the tank with a correcltly measured mixture of oil and fuel, and can then see if the issue resolves itself.
06-13-2014 04:51 PM
dabnis
Re: 9.8HP Tohatsu 2-stroke odd behaviour

Unless you have a rather severe air leak, it sounds like a restriction in your high speed jetting or, maybe some restriction in the float bowl valve. Other possibilities, dirty fuel filter(s), faulty fuel pump, tank not venting properly, kink in a fuel line, & so on.

Before taking the carb off, try dropping the float bowl, turn on the fuel & "tickle" the float
up & down, possibly flushing out any debris in the valve. Did this on my generator a while back & it saved me from having to remove the carb.

It has been my experience with electronic ignitions, barring loose/dirty connections, that they either work or die, not much in between.

Paul T
06-04-2014 03:01 PM
Zanshin
Re: 9.8HP Tohatsu 2-stroke odd behaviour

I could have had a multihull dinghy

But CalebD already mentioned something in the first which might be the cause, a bad oil/fuel mix ratio. That might fit, since it has been a long time since I filled up the outboard fuel tank and remember that when I did so I was in a hurry and didn't actually measure the oil but poured in what I thought was about the right amount. In retrospect, I might have put in quite a bit too much oil. The tank is getting empty so I'll know soon if a new tank fill does the trick.
06-04-2014 01:19 PM
CalebD
Re: 9.8HP Tohatsu 2-stroke odd behaviour

Since I know this is your engine for your dinghy I shouldn't have to ask if it is a mono or multi hull, should I?
06-04-2014 12:41 PM
Zanshin
Re: 9.8HP Tohatsu 2-stroke odd behaviour

CalebD - you are too cruel in your response, too cruel indeed!

[in chat I mentioned I'd posted this question here, and then wondered how long it would take to have the thread contain one of a list of words. CalebD has used them all, within minutes of my posting..
Wait, he missed "catamaran"/"monohull"]
This thread has more than 10 replies. Click here to review the whole thread.

 
Posting Rules
You may post new threads
You may post replies
You may post attachments
You may edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On


All times are GMT -4. The time now is 06:07 PM.

Add to My Yahoo!         
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
SEO by vBSEO 3.6.1
(c) Marine.com LLC 2000-2012

The SailNet.com store is owned and operated by a company independent of the SailNet.com forum. You are now leaving the SailNet forum. Click OK to continue or Cancel to return to the SailNet forum.