mariner fourstroke 9.9 hp help please

[davidmichael]

Hi can anyone give me their two penny piece please. My newly purchased secondhand Mariner fourstroke 9.9hp outboard was giving me trouble today.



It works on idle but when engaging the forward gear it works for short while then makes a funny mechanical noise as though something is loose in the engine and then it just dies. Then takes a while to start again. Any suggestions very welcome. Or if you know of an reasonably priced outboard mechanic near Barnet or St Albans. Thanks


PS we checked the oil and plugs all good and the engine itself looks like it has only had little use.

[Peter_C]

Could be a pre-detenation issue (We can't hear the engine die from behind our key boards), but mechanical noises are rarely normal. The first thing to do is make sure it has fuel. Do the RPM's jump up just before dying? Try pumping the fuel primer bulb. Is it hard in half a pump or so? How much fuel is in the float bowl? Spray a small shot of starting fluid or carb cleaner into the carb if it doesn't restart. Does it start now? What year is the engine? Was it stored more than used? Does it pee out the tell tale while running? Is the motor overheating? How long after starting and running the engine does this occur?

The most likely issue is the carb, of course it could be another issue altogether.

[Fenlander]

Was this on the water or in a test bucket? Are you familiar with outboards at all? A private purchase I guess. If for example there was a carb blockage happening after a short while with a bit of load on in gear then as it misfires and dies it could sound "rattly". I'm thinking perhaps sediment in the carb bowl pulling up into the jets??

A video with sound would help if that was something you could do?? But as Peter hints carb most likely assuming the noise is a false trail... but otherwise it could be anything.

For someone local to you then...

https://www.ribs.co.uk/

[davidmichael]

Thank you Fenlander and Peter C for your hasty input and ideas. I am not familiar but had my car mechanic with me who knows a bit more than me. No it wasn't in the bucket. Hopefully my uploads will give some more clues. I am getting the message that video uploads not allowed. Is there a way to upload them? Thanks!

[davidmichael]

Originally Posted by Peter_C

Could be a pre-detenation issue (We can't hear the engine die from behind our key boards), but mechanical noises are rarely normal. The first thing to do is make sure it has fuel. Do the RPM's jump up just before dying? Try pumping the fuel primer bulb. Is it hard in half a pump or so? How much fuel is in the float bowl? Spray a small shot of starting fluid or carb cleaner into the carb if it doesn't restart. Does it start now? What year is the engine? Was it stored more than used? Does it pee out the tell tale while running? Is the motor overheating? How long after starting and running the engine does this occur?

The most likely issue is the carb, of course it could be another issue altogether.

Yes it has unleaded fuel plenty. No RPM's didn't seem to jump it just suddenly cut out.


I did pump fuel primer bulb. I think the engine is 5 years old with minimal usage. Yes stored more than used but previous owner said there were no issued last time they were on the water. yes the water cooling system is working with water coming out the side while running. Initially we were able to travel a mile down the river then it cut out. After that it cut out every few minutes and towards the end it cut out straight away. We were wondering if it is the gear that is shot. Do these engines have a thermal cutout? Is the engine cover supposed to get quite hot to the touch? Thanks!

[Fenlander]

Of course remember this is at a distance guesswork but...

By and large a mechanical problem is not that likely on a low leisure use 9.9, a motor that is usually reliable. Also a mechanical issue is usually there or not rather than coming and going with time.

Re overheating with the temperatures of the past few days I'd expect the cowl to feel hot. If it is up to the mark on oil and has a good tell tale jet then overheating seems an unlikely cause.

Re oil I know you have checked it's topped up but I remember that model has an oil pressure warning light on the front. What I can't remember is if it has any input to the ign to restrict revs or even cut out if it determines low oil pressure?? If this were the case it's not unknown on engines in general for the sensor to fail and cause a false slow/shut down.

The more you describe it the more it sounds like fuel starvation though. You need to check the whole feed from the tank pickup through the primer bulb to the under cowl filter, fuel pump and carburettor. I hesitate to ask but you did unscrew the fuel tank vent screw??

Re checking the fuel supply there could be a blockage at the bottom of in tank pickup pipe, the pipe can sometimes come dislodged at the top inside so it pulls in air, the primer bulb one way valve can fail, the fuel hose can have an internal blockage anywhere along its length (more likely if a grey Quicksilver pipe**), the small fuel filter under the cowl could be blocked with debris, the fuel pump on the back of the engine could have failed or have a weak output and finally there could be debris in the carb float bowl and/or jets.

**I think I can see in one image you have the original 12l Quicksilver tank with grey fuel line. What can happen with this particular fuel line is that it's construction is the outer grey flexy with a bonded in plastic inner tube. Over time the inner tube de-laminates from the outer then breaks up and blocks the line.

Regarding things that cause a motor to stop as they warm up this can happen with an ignition component that is failing once warm... but it is so rare in general and particularly on a motor of this age that I'd be looking at everything else first.

An intermittently faulty kill cord switch can cause cutting out but its usually total stop or random but not related to time run.

In any case I would be wanting to get the outboard in a bin of water and just do a few basic checks before taking to a dealer.

[davidmichael]

Originally Posted by Fenlander

Of course remember this is at a distance guesswork but...

By and large a mechanical problem is not that likely on a low leisure use 9.9, a motor that is usually reliable. Also a mechanical issue is usually there or not rather than coming and going with time.

Re overheating with the temperatures of the past few days I'd expect the cowl to feel hot. If it is up to the mark on oil and has a good tell tale jet then overheating seems an unlikely cause.

Re oil I know you have checked it's topped up but I remember that model has an oil pressure warning light on the front. What I can't remember is if it has any input to the ign to restrict revs or even cut out if it determines low oil pressure?? If this were the case it's not unknown on engines in general for the sensor to fail and cause a false slow/shut down.

The more you describe it the more it sounds like fuel starvation though. You need to check the whole feed from the tank pickup through the primer bulb to the under cowl filter, fuel pump and carburettor. I hesitate to ask but you did unscrew the fuel tank vent screw??

Re checking the fuel supply there could be a blockage at the bottom of in tank pickup pipe, the pipe can sometimes come dislodged at the top inside so it pulls in air, the primer bulb one way valve can fail, the fuel hose can have an internal blockage anywhere along its length (more likely if a grey Quicksilver pipe**), the small fuel filter under the cowl could be blocked with debris, the fuel pump on the back of the engine could have failed or have a weak output and finally there could be debris in the carb float bowl and/or jets.

**I think I can see in one image you have the original 12l Quicksilver tank with grey fuel line. What can happen with this particular fuel line is that it's construction is the outer grey flexy with a bonded in plastic inner tube. Over time the inner tube de-laminates from the outer then breaks up and blocks the line.

Regarding things that cause a motor to stop as they warm up this can happen with an ignition component that is failing once warm... but it is so rare in general and particularly on a motor of this age that I'd be looking at everything else first.

In any case I would be wanting to get the outboard in a bin of water and just do a few basic checks before taking to a dealer.

Thank you so much for taking the time Fenlander.



I hesitate to ask but you did unscrew the fuel tank vent screw??


Yes. My mechanic also thought that it was an issue with fuel getting to the engine but when we heard the clinking sound he thought it might be a gear issue. We could hear a similar sound when pulling the pull chord. Not every time but quite often.
He took off the carb and made sure fuel was getting to it. Is there a way to upload a video on here?

[Fenlander]

Videos are tricky to try and put up directly so most folks upload to Youtube and link.

[davidmichael]

Just had a chat with the friend mechanic who was with me yesterday. He said that when the motor is running on idle it runs perfectly. The problem is when you engage the gear it make an odd noise which he says comes from the gear box and then it stalls.

[Fenlander]

That sounds really odd and very unusual that there'd be problems in the gearbox of a low use motor such it would lock up and stall. I think it's a case of over to your mechanic as he's got it in front of him... but....

I have to ask is this guy an experienced outboard mechanic as well as car mechanic? If he doesn't know outboards then I'd be saying very grateful, no disrespect, and taking it to Barnet Marine.

The eventual outcome will be interesting and I hope not expensive.

[davidmichael]

https://www.youtube.com/watch?v=eKAKvnnxlHM

[davidmichael]

Originally Posted by Fenlander

That sounds really odd and very unusual that there'd be problems in the gearbox of a low use motor such it would lock up and stall. I think it's a case of over to your mechanic as he's got it in front of him... but....

I have to ask is this guy an experienced outboard mechanic as well as car mechanic? If he doesn't know outboards then I'd be saying very grateful, no disrespect, and taking it to Barnet Marine.

The eventual outcome will be interesting and I hope not expensive.

no he doesn't know a thing abut outboards and I wouldn't want him to try to solve the issue. OK Barnet workshop sounds like a plan!


It doesn't cut out instantly it cuts out in a few seconds. So it works as it should and then cuts out after 10 seconds. But this cut out time varied from when it first started from 10 minutes to 5 minutes to 2 minutes to seconds.

[Fenlander]

>>>If he doesn't know outboards then I'd be saying very grateful, no disrespect, and taking it to Barnet Marine.

I say this because for example...

You have the tiller combined throttle/gearshift. When you turn it into gear the revs are so low if there is a carb/fuel supply or any other tuning/running problem they will stall as soon as they go in gear. Even happens if not fully warmed up and you misjudge the amount of choke. Even when running properly given outboard gearboxes are quite crude there will often be a light ching/clonk as they go in gear... and if they stall when put in gear the backlash as they stop can make a noise that could sound like a fault.

So if he doesn't know outboards he could end up going off in the wrong direction re a diagnosis.

[Fenlander]

It's obviously hard to tell via a video but that sounds quite fast for an out of gear idle... however it's running smoothly and sounds as I'd expect. Of course we don't get to hear the stalling noise.

[davidmichael]

Originally Posted by Fenlander

>>>If he doesn't know outboards then I'd be saying very grateful, no disrespect, and taking it to Barnet Marine.

I say this because for example...

You have the tiller combined throttle/gearshift. When you turn it into gear the revs are so low if there is a carb/fuel supply or any other tuning/running problem they will stall as soon as they go in gear. Even happens if not fully warmed up and you misjudge the amount of choke. Even when running properly given outboard gearboxes are quite crude there will often be a light ching/clonk as they go in gear... and if they stall when put in gear the backlash as they stop can make a noise that could sound like a fault.

So if he doesn't know outboards he could end up going off in the wrong direction re a diagnosis.

I totally agree thanks for that. I would feel better taking it to an ouboard mechanic. And the other issue I had was trying to tilt the motor back it was very hard to get it to stay up at an angle even though there are preset grooves for the pins to rest on.

[Fenlander]

Re the tilt the mechanisms they are often forgotten and unlubricated from new so they don't spring into the interim positions. Simply oiling/greasing will do the trick.

[davidmichael]

Originally Posted by Fenlander

Re the tilt the mechanisms they are often forgotten and unlubricated from new so they don't spring into the interim positions. Simply oiling/greasing will do the trick.

Thanks for the help. The support on here is second to none and really grateful you have taken some of your Sunday to help.

[Mikefule]

If it's the "twist to engage gear" model, you do know to click it firmly and definitely into gear. Do not try to ease it in gently. If you ease it in, you will get a noisy mashing of gears. The clutch is mechanically very simple: it clicks in and it clicks out, with no subtlety or slipping.

[davidmichael]

Originally Posted by Mikefule

If it's the "twist to engage gear" model, you do know to click it firmly and definitely into gear. Do not try to ease it in gently. If you ease it in, you will get a noisy mashing of gears. The clutch is mechanically very simple: it clicks in and it clicks out, with no subtlety or slipping.

Hi Mikefule thanks. I didn't know that but by default we tried the various permutations and when the gear is fully engaged it still suddenly cuts out.

[Mikefule]

Originally Posted by davidmichael

Hi Mikefule thanks. I didn't know that but by default we tried the various permutations and when the gear is fully engaged it still suddenly cuts out.

Have you changed your gearbox oil?