4-Stroke outboard motors ????

[Chuck R]

Nissan- Tohatsu- Mercury Motors.

I grew up with 2 stroke Johnsons, Evinrudes and Mercury outboards. But my experience with these new 4-strokes 5 HP has not been exactly pleasant.
My new to me 222 O'Day came with an almost new Nissan 4-stroke outboard that was made by Tohatsu. They also make the Mercury 4-5 & 6 Hp motors too. Previous owner only used the motor about four times the prior season when he bought it new. During my first season I could never get it to idle smoothly. Adding SEAFOAM FUEL CLEANER helped but it still was threatening to stall out when docking the boat. Last winter I decided to bite the bullet, Ordered the carb kit new fuel pump, fuel filter. thermostat and changed out the fresh water impeller. This year it has been working perfectly until three weeks ago. It stopped dead coming into the channel (with rip rap and hugh boulders) lined on both sides. Not a good place to quit !! Good thing the wind was blowing straight down the channel from aft as we were able to drift over to the gas dock. There I tried to start the motor. It took many tries and after taking out the fuel filter and blowing backwards through it I could get the motor to run. Now it would die when I put it in gear. After running in neutral it finally would run if I didn't give it to much throttle.
Well I figure the carb is again dirty. So again I cleaned the carb, the gas tank and put in a second fuel filter at the gas tank. Put the motor on the boat and ran it fine at the dock, then decided to put it in gear and at an idle it ran good ,but when I gave it more throttle ( very fast idle ) after 10 minuets it stopped dead just like it did in the channel.

Took the motor to a local outboard repair service shop who said dirt in the fuel and carb told them I cleaned both carb and tank. $80.00 later I get it back on the boat and sure enough it ran 10 minuets and quit. The shop said it ran an hour no problem and that there was dirt in the carb and needed an adjustment. Took it to a second shop thinking it would be an ignition part that breaks down under heat or a load. But this shop also says a fuel problem after a week I get a call saying he does not understand this issue and that he has given up. Everything checks out fine, fuel system ignition, and it should run. I did not fix the problem therefore no Charge.

I have now found a Nissan dealer about 40 miles away and will be taking it there. hind sight easier than foresight huh.

I just wonder if anyone with a 4-5 or 6 HP Tohatsu, Nissan or Mercury has had issues like me? Wish we could still buy the 2 stroke engines.

 

[Don S/V ILLusion]

Wish we could still buy the 2 stroke engines.

You can! Whether or not you can use it is a function only of your location but they are widely available. Hope you get your's fixed and it doesn't come to that.

 

[ITMaster]

I have had the same problem

with my Merc 4 horse 4stroke. First off, my owners manual says specifically to not use gas with methanol or ethanol in it. I don't have any choice, that is the first problem. I bought the motor new in 2004. At the beginning of this season, the same thing happened, as happened with you, and this had been happening last year also. We ordered a new carb and pump and waited over 8 weeks for it. $350 later, I was good to go and went, for one weekend and it did the same.
I had some lucus on board and dumped it in the fuel tanks. that helped a little bit. I got some CRC fuel stabilizer and added enough for a gallon of gas and got a fresh gallon of gas and used that. I also got some water zorb, and added enough for a gallon of gas.

The motor runs much better, I use it, it will start on the second pull, I disconect the hose from it, shut off the fuel valve and let the engine run until the carb is empty.

This seems to have helped me out with my situation, maybe that may work for you. good luck, tom

 

[oldiesrocker2001]

Merc Outboard first-time-out starting problems

I had gas issues with my Merc 4hp. I used it pretty extensively a couple of summers ago where there was more than a mile to open water from where I was docked on vacation. Never a single problem. the following year(last summer)it workd fine one day, then 2 days later refused to start. Except on that vacation I always had run out the fuel at the end of the day, but was told eventually that I needed a new carb that summer due to bad fuel. I had it replaced;winterized and stored it until this season. Despite a fresh tank of gas with Stabil in it and even draining the fuel line before starting out the season the motor ran unevenly when it started(after about 30 pulls) at the beginning of each day's use. Up to 3 hours later on the same day, though, it would start on the first pull and run fine. We haven't figured out the problem yet.

 

[Chuck R]

Plan to disconnect >>>>>>>

One of the shops asked me if I disconnected the fuel line and let it run out of gas. When I said no they asked will how often do you use the motor. Answer is a minimum of once a week as we race on Wednesday evenings. But we use it maybe two to three other days a week too as I am retired. They said we that should no make a difference. Plan on doing that regime when it gets back to running again.

 

[Chuck R]

After reading other threads on this forum,,,,,,

I found that there were people who have had good luck with these motors and speak highly of them.. So thus, I decided to post this complaint and see if others like them too....????? Let's see what we get.. Fish'n for some answers. Thanks for the bites.

 

[Rick Webb]

A Buddy Had the Exact Same Problem With a Honda

I kept cleaning the carb and it would be better but not fixed. After he paid a mechanic a bunch of money in Marathon he replaced the carb (we should have done that in the begining). He has not run it since November now and I am sure it is going to be the same story all over when we go to start it.

 

[CharlieCobra]

I ALWAYS run the carb dry after shutting off the fuel.

I did that on my older 2 strokes and still do it on newer OB's.

 

[Bert17825]

Check the filter INSIDE the tank

Not sure if you already checked this, but many portable tanks have a filter in the fuel pickup tube inside the tank. Also, swapping for a known good tank and hose/primer bulb might isolate the problem if it is not the carb.

I have two Tohatsu/Nissans and one Mercury. They have been great. There is really not much to the carbs, very simple design.

I have had to clean the carb (disassemby and a good soaking overnight in carb cleaner) and blow out passageways with compressed air on the Nissan that had not been used by the previous owner for an extended period. The motor would not idle properly and the soak and reassembly fixed it.

Your problem sounds like a fuel starvation problem, since it will idle but not run up. Could be the main jet, but I would bet on fuel starvation. Can you tell if there is fuel in the fuel bowl when the engine dies by opening the drain at the bottom of the bowl? No fuel in the bowl would narrow down the suspects.

Good luck,
Bert

 

[caguy]

For the last few months when I drank from my travel coffee cup,

the kind with the top and sip hole, the coffee would barely come out while I was drinking, as I would remove the cup from my mouth the cup would free flow all over my shirt. Today I had the same cup but had some time to think about it and analyze it. It turns out that when I would go to drink my nose would touch the ergonomically misplaced vent hole.
The point... it could be as simple as a plugged vent hole. It would not show up at the shop if they use their own gas can.
If it doesn't help with your motor it may save a few shirts from stains.
Frank

 

[Ross]

Caguy, You need to see somebody about

relocating your nose or you need to drill an extra hole in yer cup. ;D

 

[RichH]

Ditto - CharlieCobra

To avoid almost all 'carb problems', even when using a stabilizer, I ALWAYS run the carb dry.

For long term storage (and with the carb previously run dry) I will remove the main jet adjusting needle, carefully noting how many turns in and out, and then squirt in some isopropyl alcohol to flush out the needle seats. Such carbs are very easy to adjust.

Only use 'fresh' fuel in an OB if you dont want 'problems'. Without stabilizer I wont use fuel that is over a month old, with stabilizer - 6 months.

 

[s sauer]

Alcohol resistant Fuel lines?

Most all gas stations now have up to 10% alcohol which could attract water or attack some gasket and/or fuel lines. New CG approved fuel lines are alcohol resistant. I'd clean out the tank, replace the fuel line and include an in line filter ahead of the float bowel.

 

[bffatcat]

Its the gas

I purchased a new 8hp 4 stroke tohatsu new this season. I take care of all the
maintenence and repairs on the boat with the exception of the motor. unfortunately I dont know much about motors. The dealer told me do not use gas that is over a month old. I have had no trouble yet. Most of the repair people I know all say the same thing. These outboards dont like ethanol. Use fresh gas you will have less trouble.

 

[Rick Webb]

Avgas

I wonder if they are putting alcohol in avgas? Night be worth checking with the FBO at the local airport

 

[jimg]

4 strokes and ethanol

I have seen this many, many times with almost new small 4 stroke outboards, and in my opinion it's the ethanol in gasoline that's the problem Ethanol is hydroscopic. It will extract water from the air, the more humidity, the more water. Water is heavier than gasoline and will accumulate at the bottom of the tank. The smallest amount of water in the fuel will cause stalling and make the engine impossible to start. On 2 strokes it causes damage by diluting the fuel/oil mixture, but on 4 strokes, with leaner mixtures, half the firing cycles, and higher compression, they simply won't run. I know that it is not practical, but I would bet that if every time this problem happened, you were to drain the float bowl and the fuel line to the carb, and put new gas in, it would run.

 

[BBC16385]

Gumout for 4 strokes

We have the 3.5 Mercury in its second season and experienced everything you described. Would not idle, would not start. Sometimes it would take 35 pulls to start. Once it started it ran great wide open, but would cut off on idle.

I bought carb and fuel system cleaner made for autos. Put a little in my 2 gallon gas tank. After several tanks in the Mercury, it seamed to run better. Then I realized, from the huge signs they have put up, that several marinas in Deltaville are selling nonethanol gasoline. I bought some, 93 octane. Put some carb cleaner in it too.

Halfway through the first tank, the Mercury started running like it was brand new. Idles great, starts on the first pull every time.

Amazing. It fixed itself. I used the Gumout product. I recommend this approach to anyone who has one of the low HP 4 stroke engines.

 

[guest]

We love our 9.8. Runs perfectly - dependable.

Do all my own maintenance and refuse to let the local authorized service dealer near it. Those yokels have ruined more engines for folks over the years.
Here's a link you may find interesting - http://forums.iboats.com/Tohatsu-Outboards/

 

[walt]

Ive heard of people having problems with the fuel hose connector on that engine. Are the shops using a different fuel hose when they say everything is good?

Ive got two small outboards, an old Honda 8 hp and a newer 4 hp Tohatsu - both 4 strokes. Ive got several two stroke chain saws. I have problems starting all of them. My lawn mower gets terrible neglect.. but starts first pull everytime. Im thinking maybe neglect may be the key to making the outboards start easier.

 

[kloudie1]

Aviation gasoline cannot have oxygenates in it.. that is to say alcohol.. so if you can get a buddy to get a few gallons for you, you’d have ethanol/methanol free fuel. Additionally, some small planes’ engines have approval from FAA to burn automotive unleaded fuel but it cannot have alcohol in it. Ya might be able to find a small local airfield where you’d be able to buy that fuel (82 UL avgas). Here is another item of interest.. the fuel pump at the automotive stations must be labeled as having alcohol if it is included in the blend.. Many states have an exception for small independent gasoline suppliers that allows them to sell automotive gasoline (mogas) into which alcohol has not been mixed. These are the non majors and discounter stations that you see. If you can find a pump at one of these brands that does not have the sticker, that fuel does not have ethanol in it. I recently found my local Racetrack station has no alcohol in the fuel and that is where I buy fuel for my standby “Hurricane” generator. The fuel must last all summer and with some preservative added, and no alcohol, it does. It goes into the car at the end of the season if it hasn’t been used for making electrons move ..