engine problems?

[Bitsmith2k]

hey guys, i'm hoping someone can help me out here..

 

so i picked up a boat in the spring.. due to my arm injury it has only seen the water once in early june (and i didnt even get a chance to drive it).. we noticed the motor sounded a little rough (and slow) on full throttle.. i figured i wouldnt worry about it until i was healed enough to use it again.. this friday i'm hoping to get it out for the day so today i start to get it ready..

 

i tested the compression on both cylinders (was good), changed the plugs and fired er up.. starts on the first pull.. it'll rev really low for a couple seconds and then, what i can only explain as a backfire, happens and the motor dies.. i ran carb cleaner through it and that seemed to help, if i give it a fraction of throttle it will run fine..

 

 

is this something i should be worried about? any ideas of whats happening with it? i'm not a mechanic by any means..

 

the motors a '89 25HP Yamaha 2 Stroke 25LF..

 

thanks guys

mike

[2 tone z71]

sounds like ya got some water in your fuel ,only 2 things will cause backfire water or electrical ,drain your tank and carb ,pull the bowls off if your able have a look around blow the orfices in your carbs out with air,fill up with fresh fuel maybe a new set of plugs and you should be good as gold,worst case it may be a coil breaking down but I bet its something simply

[Dabluz]

Most outboard engine problems are due to a dirty carb and water in the carb. Look in the gas tank to see if there is any rust etc too. If there is a fuel filter, you can change it and if there is no fuel filter, install one.

[Greencoachdog]

Most outboard engine problems are due to a dirty carb and water in the carb. Look in the gas tank to see if there is any rust etc too. If there is a fuel filter, you can change it and if there is no fuel filter, install one.

 

 

Yeah, dirty sticky gummy carb, had that problem back in the spring. A rebuild job on the carb will prolly make it run like new.

[pikehunter]

Yep Mike the above guys prob hit the nail on the head.

 

Had similar trouble a couple of times with old gas and last year even with new gas as I kept topping up the tank and water managed to form in the bottom although I had been using Johnson/Evinrude fuel stabilizer I still had a problem arise.

Edited August 7, 2008 by pikehunter

[PatrickGG]

Johnnybass had the same problem i cant recall what it was that fixed it "it was minor" give him a p.m i am pretty sure it sounds like the same symptoms and he also has a yamaha 40 hp motor.

[ecmilley]

there's a product called sea foam that will work great at getting rid of gum and varnish run this through the engine, get some fresh fuel and that should solve the issues, but being an 89 it could be due for a carb overhaul

[Bitsmith2k]

there's a product called sea foam that will work great at getting rid of gum and varnish run this through the engine, get some fresh fuel and that should solve the issues, but being an 89 it could be due for a carb overhaul

 

thanks for the help guys..

 

ive got a bottle of seafoam, should i just add it to the fuel or dump it into the carb?

 

for a carb overhaul, i take it i need a rebuild kit? is there anywhere local (mississauga / gta ) that i can grab one?

 

thanks again guys...

[Fish4Eyes]

You put the seafoam in your tank. Although I am having the same engine problem as you are and the seafoam did not help me at all

[davew3]

Get your coils checked. Had the same issues years ago. Put in new gas and treatment, still bad. Micro cracks in the coils.

Good luck.

[Wild]

Plenty of places in the GTA to get a kit Mike but are the gaskets in bad shape or will they tear when dissembled. How is the spark? pull the plugs and ground them, turn the engine over and check for a clean strong spark. Also make sure the exhaust is not blocked. Before the seafoam spray the jets and passages with carb cleaner and check the float level.

[Bitsmith2k]

Plenty of places in the GTA to get a kit Mike but are the gaskets in bad shape or will they tear when dissembled. How is the spark? pull the plugs and ground them, turn the engine over and check for a clean strong spark. Also make sure the exhaust is not blocked. Before the seafoam spray the jets and passages with carb cleaner and check the float level.

 

i'm going to assume that the sparks good, i got a good jolt off it when i pulled the boot off the plug..

 

i'm beginning to think that i might have to find someone to take a look at it.. the carbs not the easiest thing to get at, though i'm positive i can take it apart my confidence goes down considerably when i think about putting it back together.. i dont want it to end up as a box of parts, which is what usually happens when i take things apart..

[Wild]

Assembly should not be a big deal you just need to pay attention to details and of course a good manual as a guide. PM me if you need help.