Tohatsu 5hp 4-stroke dies

Feb 26, 2004
161
Hunter 23 Lake Keystone, OK
I have a Tohatsu 5hp 4-stroke, just a few years old. Having carb problems I think. I use real gas.
I have to pull the choke all the way out to start it. Start reducing the the choke too far and it dies. Accelerating also kills it.
I disassembled the carb and used carb spray three times. I find three jets to clean. Two of them you can see through, and spray through. The third one you can't see through and carb spray won't go through it.
It sits on top of the longest jet.
Is it stopped up or just designed that way.
Thanks in advance,
Mac
 
Feb 10, 2004
3,522
Hunter 40.5 Warwick, RI
Disclaimer: I do not have this engine. However, the dealer of my local marina tells me that small four stroke outboards (under 10hp) have such small passages in the carburetor that the only way to effectively clean them is to disassemble the carb and clean the passageways with an ultrasonic cleaner. The passages in a two stroke are not nearly as small so the cleaning problem is not as severe. FWIW, after having 5 years of problems with my 3.5hp Nissan two-stroke, I cleaned the carb in an ultrasonic cleaner and replaced all the jets and needles. I use only non-ethanol gasoline and have had no problems in two years. From your problem description, I suspect that the hi-speed passage is clogged. If this engine has an accelerator pump that may also be malfunctioning. I hope this is of some help.
 
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Gunni

.
Mar 16, 2010
5,937
Beneteau 411 Oceanis Annapolis
Yep, you have clogged jet(s). You need to get it clean and the rest of the internal surfaces. Some folks have good results with an ultrasonic cleaner. Properly manage your fuel.
 
Nov 13, 2011
161
Oday 23 New River Az
Just curious. Is this fresh new fuel? Water in fuel will cause the same results. Pump some into a glass jar to decant and check for water.
 

Gunni

.
Mar 16, 2010
5,937
Beneteau 411 Oceanis Annapolis
No doubt the engine has seen water-contaminated fuel. Once the water corrosion has happened it does not matter if you change the fuel, you have generated the solids that clog the jets. You have to scrupulously manage the fuel always or this is your reward.
 
Feb 17, 2006
5,130
Lancer 27PS MCB Camp Pendleton KF6BL
Would it be worth it to just purchase a new set of jets. Then you can swap them out, say yearly, and keep one set in cleaner while the other set is in use.
 

Sailm8

.
Feb 21, 2008
1,719
Hunter 29.5 Punta Gorda
I don't think this is your problem but is just FYI. The plastic fuel line clip that attaches to the engine is a proprietary piece. It looks just like you could get one off the rack but there is something different about the part. The non proprietary clip will start to leak air causing the engine to die. I have the same motor and found this out the hard way.
 
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Gunni

.
Mar 16, 2010
5,937
Beneteau 411 Oceanis Annapolis
Would it be worth it to just purchase a new set of jets. Then you can swap them out, say yearly, and keep one set in cleaner while the other set is in use.
You have to scour the entire carb of corrosive hydrates otherwise the jets will clog right back up. I have a spare carb and am shopping for a small ultrasonic cleaner to see if I can rejuvenate a corroded carb.
 
Feb 10, 2004
3,522
Hunter 40.5 Warwick, RI
Gunni-
I bought this model ultrasonic cleaner on eBay - see link below. It is a 2 liter size with 70W sonic power and 50W of heat power. I cleaned my carbs using dunk-type carb cleaner and ran the ultrasonic cleaner for 30-45 minutes with hot cleaner. I not only cleaned my outboard carb, but also my string trimmer and chain saw carbs. All machines are running without problems since 2015 on E0 gasoline.
https://www.ebay.com/itm/Jeken-PS-1...634600?hash=item1a4c24df68:g:LbAAAOSwY~1aCnT2
The prices are much higher now than in 2015. No clue as to why that is. The good news is that you will find additional uses once you have it.
 
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Sep 25, 2008
615
Morgan 415 Out Island Rogersville, AL
Gunni-
I bought this model ultrasonic cleaner on eBay - see link below. It is a 2 liter size with 70W sonic power and 50W of heat power. I cleaned my carbs using dunk-type carb cleaner and ran the ultrasonic cleaner for 30-45 minutes with hot cleaner. I not only cleaned my outboard carb, but also my string trimmer and chain saw carbs. All machines are running without problems since 2015 on E0 gasoline.
https://www.ebay.com/itm/Jeken-PS-1...634600?hash=item1a4c24df68:g:LbAAAOSwY~1aCnT2
The prices are much higher now than in 2015. No clue as to why that is. The good news is that you will find additional uses once you have it.
Rich, golly, you da man. Great advice. Thanks.
 

CarlN

.
Jan 4, 2009
578
Ketch 55 Bristol, RI
Check the price of a new carburetor. I bought a new one for my Honda for about $150. Took 30 minutes to install. That cost less than having someone work on it. I wonder if you got some ethanol fuel without knowing it? I only get gas at places that specifically say "no-ethanol". Another trick is to get a few quarts of Truegas at Lowes or Home Depot and use it for a while. It was a miracle cure for a balky outboard of mine.
 
Jul 27, 2011
4,552
Bavaria 38E Alamitos Bay
I have a Tohatsu 5hp 4-stroke, just a few years old. Having carb problems I think. I use real gas.
I have to pull the choke all the way out to start it. Start reducing the the choke too far and it dies. Accelerating also kills it.
I disassembled the carb and used carb spray three times. I find three jets to clean. Two of them you can see through, and spray through. The third one you can't see through and carb spray won't go through it.
It sits on top of the longest jet.
Is it stopped up or just designed that way.
Thanks in advance,
Mac
I have a 2000-yr model of this engine that I've used a lot. I can't say I've ever been "happy" with it; although it does the job most of time. Seven years ago (2011) I took it to an authorized service location in Costa Mesa b/c it was showing symptoms like the ones you describe. For around $100-125 (labor & parts) they serviced the carburetor. After that it has functioned reasonably well with only minor starting issues. But I think it's about time for another service call as some of those earlier symptoms are starting to reappear, particularly regarding the choke and acceleration.;)
 
Jul 21, 2016
42
san juan 7.7 wabamun
I have the same outboard. This spring launch it had the same problems. I put in a new fuel filter and spark plug, and now it starts and runs perfect.
Try the cheap and easy fixs before ripping the carb apart.
 
Nov 26, 2012
1,557
Hunter 34 Berkeley
That totally sounds like water/ethanol contaminated gas. I had a similar engine with exactly the same problem. I had to take the carb apart and clean it. One thing I did that helped tremendously was install a fuel filter in the line from the remote tank to the engine. I put it as close to the engine as I could. This is because ethanol in the line actually dissolved the rubber and sent the goop into the carb. The other thing I did was buy an extra carb. I always had a clean carb ready to go.
 
Feb 26, 2004
161
Hunter 23 Lake Keystone, OK
Sorry it's taken so long to give you an update. Appreciate all the help, very interesting information. I tried cleaning the jets with the spray cleaner twice and the results were not real good. Also replaced the filter. Wife bought me an ultrasonic cleaner for Christmas and it did the job, although the motor still doesn't run as smooth as before. Doesn't want to idle. The one thing I haven't tried is a new sparkplug. Dang. I'll jump on that.
 
Nov 21, 2012
295
Yamaha 33 Port Ludlow, WA
A replacement carb can can be purchased on Amazon. You can use the carb for the 6hp model. They are an exact fit and the only difference between the 5 and 6 hp engines. Cheap upgrade if you're replacing it anyway.
 

NYSail

.
Jan 6, 2006
2,747
Beneteau 423 Mt. Sinai, NY
I have the same engine..... run regular fuel with a stabilizer and it starts with no problem first pull every time. At the beginning though I did not use stabilizer and had trouble starting and running....... I have used stabilizer since.

Good Luck
 
Sep 25, 2018
244
Catalina Capri 22 Capri EXPO 14.2 1282 Stony Point
Can't get E0 gas in the NYC area. Nearest available is 80 miles north. One Sunoco station in NJ sells racing fuel. 100 octane and $10 per gallon. Stabilized gas seems to work OK, mostly. Erratic idle and occasionally need to choke while running to get enough gas through the clogged jets. Plan to pull the engine apart over the winter if I find the time between skiing trips.