# Mercury 8-hp Problems



## seb5thman (Sep 24, 2008)

I hope this is the right forum for this question. I have a 2007 Mercury 4- stroke 8-hp outboard that gives me fits. It is connected to a 2.5 gal container with a bulb type primer. After priming the bulb the boat won't start half the time. I can smell gas so I think it's flooding, but it even does it on occasion when I only prime the bulb a couple of times. After waiting 15-minutes or so it will *sometimes* start, and if it does a lot of white smoke comes out. Other times I have to pull it 30+ times before it begins to sound like it wants to start. 
The other problem is sometimes the starter handle seems to be seized up and won't allow me to pull start the engine. The engine is in neutral, and again it seems to have a mind of its own. 
This is my first time with an outboard, so any suggestions would be helpful.


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## tommays (Sep 9, 2008)

http://www.sailnet.com/forums/gear-maintenance/60033-tohastsu-8hp-4cycle-tech-questions.html

If you search this forum under Tohatsu (same as yours) you will get the low down on your problem which is generally form leaving fuel in the carb


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## 75R20 (Jun 20, 2008)

When it won't turn with the starter rope, you have most likely flooded a cylinder with fuel and temporary hydro-locked a cylinder. Next time it does it, pull the plugs and see if they are wet, and pull the starter rope while the plugs are out. It will probably turn over just fine. At the very least, pull the plugs and inspect them. They are probably junk from being flooded with fuel.
Good luck

Kary
SV Mariah
#49080


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## ChuckA (Dec 28, 2008)

The MarineEngine discussion board is the best place to get input on motors. Here is a link to their Mercury outboard forum. I've gotten a lot of great advice there.

Mercury Mariner Outboard Discussion Forum at MarineEngine.com


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## charles b (Jun 27, 2013)

seb5thman said:


> I hope this is the right forum for this question. I have a 2007 Mercury 4- stroke 8-hp outboard that gives me fits. It is connected to a 2.5 gal container with a bulb type primer. After priming the bulb the boat won't start half the time. I can smell gas so I think it's flooding, but it even does it on occasion when I only prime the bulb a couple of times. After waiting 15-minutes or so it will *sometimes* start, and if it does a lot of white smoke comes out. Other times I have to pull it 30+ times before it begins to sound like it wants to start.
> The other problem is sometimes the starter handle seems to be seized up and won't allow me to pull start the engine. The engine is in neutral, and again it seems to have a mind of its own.
> This is my first time with an outboard, so any suggestions would be helpful.


sounds like the problem i had with my mecury 4 stroke 8 hp sameyear as mine i know what was wrong with mine but some one stole it off my boat they didnt cut the lock they cut the pice tha was locked to the lock didt take the gas tank mine was leaking gas you only need to prime it acouple of times then put it in the start position


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## Sal Paradise (Sep 14, 2012)

Sounds like flooding due to a worn out float needle on the carb. You are pushing too much gas in. Try starting without priming. I never have to use the primer bulb on mine.


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## charles b (Jun 27, 2013)

sounds like the same problem i had with mine same year make model horsepower someone stole mine i new what was wrong with it did you buy it new or used i baught mine new never had a problem with it untill 2010 then someone stole it off off my boat they cut the piece thati had it locked to then i had whitesmoke comming from mine to but thats because i ran seefoam through it the nit started to leak gas and the cylender was broken i was going to get it fixed but it was stolen i still have the gas tank for it and its a 3 gallon tank that came with the motor when i baught it 
you dont need to prime it so many times that just floods the pump should only be one pull on the starting rope and make sure its in the start position white smoke how long has it been sitting becaue it will do that when its been sitting for a while also dont over fill it with oile that will wreck the motor


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## blutoyz (Oct 28, 2012)

Try one squeeze on the primer and full choke. I think you are flooding it with the primer. If it floods, open the throttle full and pull it with no choke, that will clear it out.

Just get to know the engine and you will be fine, it is finicky


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## Steve knowles (Jun 28, 2015)

I have the same problem and none of the suggestions given in this forum worked for me. I gave up It's the worst outboard I have ever owned. It has less than 15 hours on it and I have had nothing but problems. If I never disconect the gas line it runs fine but if I do it's 2 to 3 hours to get it started. If I leave the gas line hooked up for more than a week it will fill the cylinders and crankcase with gas. nobody can explane it. Buy a Honda. **** Mercury


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## capta (Jun 27, 2011)

White smoke usually indicates water in the cylinders. Are you tilting the motor too far so the prop goes above the powerhead for even an instant?
Our Johnson 4 stroke, likes choke out, no throttle for a cold start. After the first start of the day, no throttle or choke at all, but if it doesn't start on the first pull (always my fault) then it needs 2/3 throttle for the next pull. Also, there should be a little foam piece in the carb air intake on our Johnson. Without it the motor just doesn't start easily. Perhaps the Merc needs this too, and yours is gone?


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## mckinlao (Apr 8, 2018)

I have the same outboard and had the same issues till I understood how to start it. These steeps work for me every time.
1) Pull out the choke when cold starting.
2) Lightly(and I mean LIGHTLY) squeeze on the priming bulb.
3) Push in on the primer located on the outboard 3 times.
4) Give the rope starter a pull.
5) Squeeze the priming bulb a little.
6) Give the rope starter a pull.

After 4 - 6 I just keep pulling and it usually turns over. It took me a good three months to figure out how to get the outboard to start when I first bought the boat, now I can start it every time.. When I am done sailing for the day. I disconnect the gas line and allow the motor to use all the gas.

Now my biggest issue with the motor is the transmission located on the tiller. 80% of the time, I have to turn off the motor and **** it out of gear and start it back up again.


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