Why my motor speed is low 20hp mariner

[theshoaibahmed]

Hi all friend.

This morning itested the 2 cylinder and getting both 120psi. But on full speek my speed is inly 11 to 13km/hr.

Any suggestion please

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[QBhoy]

At the risk of being cheeky, might need more details.

its as simple as this...

if your 20hp is on the back of a 30ft displacement boat...I’d say you’ve got the best 20hp in the world...
mid your 20hp is on the back of a 3 metre inflatable dinghy...then you’ve got the worst 20hp in the world.

hopefully you get what I mean. Haha.

 

[flyingscott]

I told you to do a drop test or a spark test on the other forum. Did you do that??

 

[theshoaibahmed]

I told you to do a drop test or a spark test on the other forum. Did you do that??

Ok when engine running i tried take the one plg out, sound was less but engine was keep running, turn off the engine, put the plug back in, atart the engine, now took the other plug out, same sound was less but engine was keep running, tested before both cylinder got 125psi.

What could be the issue?

 

[theshoaibahmed]

At the risk of being cheeky, might need more details.

its as simple as this...

if your 20hp is on the back of a 30ft displacement boat...I’d say you’ve got the best 20hp in the world...
mid your 20hp is on the back of a 3 metre inflatable dinghy...then you’ve got the worst 20hp in the world.

hopefully you get what I mean. Haha.

Mine is 14.5ft aluminum boat with 20hp mariner outboad motor, change the stator and trigger becuse engine was not starting, service the water pump, tested both cylinders 125psi each cylinders, but when i go on water, my full speed come down to 11 to 12km/hr.

I am not technical but handy. Did oil change as well, no clue why my speed is not what its suppose to be.

Any help amd guide would really appreciate

 

[flyingscott]

Is your carb opening all the way? What happens if.you pump the primer ball on the fuel line? Has the carb been serviced lately?

 

[theshoaibahmed]

Is your carb opening all the way? What happens if.you pump the primer ball on the fuel line? Has the carb been serviced lately?

This is the only thing i didn't do yet (serivce Carburetor). What else it can be

 

[QBhoy]

So is this a 4 stroke ? If you changed the oil.

 

[Scott Danforth]

So is this a 4 stroke ? If you changed the oil.

mariners were only 2-stroke. I believe he is referring to the gear oil in the lower unit.

 

[theshoaibahmed]

mariners were only 2-stroke. I believe he is referring to the gear oil in the lower unit.

Yes my bad, i changed lower unit gear oil.

 

[Texasmark]

What year-model is your engine? If 10 or more years old, have you changed the fuel filter if it has one? Also, if it does, replace it and cut the old one open. If full of black specks change your engine fuel lines and fuel pump diaphragm (kit). If tan chips of crud, your engine to fuel tank line and bulb. I have had both these problems with my engines and these problems are easily overlooked......On my current 2002 engine, I bought last year, I don't know how many times I stared at the engine, looking right at the white fuel filter on a black engine (thing was glaring right at me) and after a lot of wasted time and money, chasing "butterflies", it was my problem on not getting WOT operation. Cutting it open it was full of tan crud from the tank to engine fuel line. On another 2002 engine I had, after 10 years on ethanol, the fuel line degraded and small black particles of fuel line clogged the filter and carbs.

 

[theshoaibahmed]

What year-model is your engine? If 10 or more years old, have you changed the fuel filter if it has one? Also, if it does, replace it and cut the old one open. If full of black specks change your engine fuel lines and fuel pump diaphragm (kit). If tan chips of crud, your engine to fuel tank line and bulb. I have had both these problems with my engines and these problems are easily overlooked......On my current 2002 engine, I bought last year, I don't know how many times I stared at the engine, looking right at the white fuel filter on a black engine (thing was glaring right at me) and after a lot of wasted time and money, chasing "butterflies", it was my problem on not getting WOT operation. Cutting it open it was full of tan crud from the tank to engine fuel line. On another 2002 engine I had, after 10 years on ethanol, the fuel line degraded and small black particles of fuel line clogged the filter and carbs.

My engine is 1998, 2 stroke, 2 cylinder.

I replaced the fuel filter already when i open the cap i didn't see any black specks but still changed it. The only thing i didn't do is service Carb.

Can some one help me about fuel pump line.

 

[flyingscott]

Answer all the questions in post #6

 

[theshoaibahmed]

Is your carb opening all the way? What happens if.you pump the primer ball on the fuel line? Has the carb been serviced lately?

I am servicing carb this week, when i pump the primer ball i can see flow of gass in filter, and primer ball get harder and harder if i continue pumping. Dont know much abiut carb, how i see if its opening full, half or not at all, was looking in youtube but cant find it

 

[theshoaibahmed]

Hi guys this morning start servicing the carb, Oh my God, seems like previous owner never serviced it. I took a part resealed and clean with carb cleaner, so now seems all good i started with one key, rightaway and checked there is no issue in carb seal or leaking gas.... All good.

Now can any one tell me how to check the speed before i go to lake to see if i got improvement or same, hoping all is good. But i want to know how i can check the speed before go to lake.

Thanks

 

[Sea Rider]

Once the motor runs strong again, without a induction tach install won't know what's the max wot rpm the motor is working at, at such low speed definitely is running lugged. Being the motor that old could have already a spun hub if prop is original, if ok, not suited to power well a large and heavy boat. Being a 2 stroke would suggest a long CRC Engine Tuner Carbon Remover applied through the carb with motor ON. Follow can instructions...

Happy Boating

 

[QBhoy]

mariners were only 2-stroke. I believe he is referring to the gear oil in the lower unit.

Sorry Scott. That’s far from true. There are many many mariner 4 strokes. There still are. I have a 2016 mariner 2.1l 4 stroke now. Available brand new currently too.

 

[Scott Danforth]

Sorry Scott. That’s far from true. There are many many mariner 4 strokes. There still are. I have a 2016 mariner 2.1l 4 stroke now. Available brand new currently too.

you have mariner decals on a mercury. Mariner here in the US ceased as an entity. however Mercury kept the name alive abroad by putting different cowl and decals

 

[QBhoy]

you have mariner decals on a mercury. Mariner here in the US ceased as an entity. however Mercury kept the name alive abroad by putting different cowl and decals

For sure Scott. Defo a mercury. They have been since the 80’s. Just pointing out that you definitely get mariner 4 strokes. They have been mercury engines for decades and Yamaha before that. But that’s not the point I suppose.
All the best.

 

[flyingscott]

Hopefully you used a good quality gasket kit with the fuel pump and primer diaphragms in it.