wont run full throttle

[numb_nuts9]

i have an 85hp force that will start fine out of gear and with throtttle forward but not in just nuetral. it was running fine one day the on the way to the docks it started to make a grinding noise and just died randomly. it started right back up but it dies if i go past half throttle...any one got an idea???

 

[foodfisher]

Re: wont run full throttle

Sounds like you have something loose or out of adjustment at the cable hookups. Gear grinding, dying (neutral safety switch) Check around there.

 

[john from md]

Re: wont run full throttle

Did it make the grinding noise while you were shifting or did it start grinding on its own?

If it started grinding and then shut down, you have mechanical damage to the engine. If you started it up afterwards, you have more mechanical damage.

We need more info.

John

 

[numb_nuts9]

Re: wont run full throttle

well some times buy noy often when i shift into gear slowly it will grind but some one told me thats normal but it dont sound normal... but it was runing just fine i was going full throttle about 32mph then it started grinding and just died. it started right back up then would only go half full speed at full throttle then die 6 min later. then i changed plugs and cleaned carbs and new fuel lines i went out again and it wont run at all if the throttle is more then half way???

 

[john from md]

Re: wont run full throttle

You are not supposed to shift into gear slowly. You are supposed to shift briskly so that you hear a thunk. Putting these engines in gear slowly wears the shift dogs.

You need to check your compression before doing anything else, including starting the engine again.

John

 

[numb_nuts9]

Re: wont run full throttle

i took it in and they said the compresion is fine? i do remember right when it happened i pushed down on the throttle and it clicked and went a bit farther then it was suposed too... ? could that have anything too do with it?

 

[john from md]

Re: wont run full throttle

What RPM did the engine get to before it shut off? Have you been using a 50:to 1 oil mix.?

John

 

[numb_nuts9]

Re: wont run full throttle

my tach is out. and yes 50:1 mix...i think it is the compresion. cuz it keeps backfiring at idle and dieing, or when im starting it.

 

[numb_nuts9]

Re: wont run full throttle

i have a compresion checker and about to go find out. but wat is it supposed to be at?

 

[john from md]

Re: wont run full throttle

From the factory, it was about 160lbs. If you get 125 to 150 with a less than 10 lb spread between cyliinders, you will be ok.

Two things you need to know.

You can't maintaine this engine without buying a Clymer Outboard Shop Manual and having some type of tachometer. As dash tachs are hard to come by, you need to at least buy one for setups and troubleshooting. Sears sells one that will work for about $35.

John

 

[numb_nuts9]

Re: wont run full throttle

ok so in the top and bottom cylenders had 100pounds pressure and the middle had none at all. it didnt even register??? could it be ther ring? or head gasket?

 

[numb_nuts9]

Re: wont run full throttle

so the head gasket is or was leaking i should say and there is slight scaring in the clyenders but not bad...

 

[john from md]

Re: wont run full throttle

If you don't see any damage, replace the head gasket and try it again.

John

 

[numb_nuts9]

Re: wont run full throttle

well on the middle cylender head there is a bit of damage. its a lil part cracked off on the top of the middle. should it be replaced?

 

[john from md]

Re: wont run full throttle

Can you send me some pics of the head and clyinder to johnandnanc182@yahoo.com?

John

 

[numb_nuts9]

Re: wont run full throttle

ok i sent 3 pics its hard too see the cracked off piece cuz glare. but one other pic shows a bit of scratchs also and these are of the middle cylinder.

 

[numb_nuts9]

Re: wont run full throttle

and the pic of the head gasket. its a bit black and when i was taking the head cover off it was too easy. i think some one before me did not tighten it all the way down so it was leaking a bit.