Yamaha 40

[andy_babs]

Hi everyone hope you can help,

I have a Yamah 40 (not sure of exact age but I think is about 20 years old)

The problem is the engine starts OK, when the choke is out out but when the choke i pushed in engine stalls (most of the time but not eveytime), when it does not stall and you go into gear it normally stalls after a couple of mins but you do get drive and go forward before stalling.

Also the engine races sometimes when the throttle is set to low before stalling, sounds like a fuel issue to me but can anyone tell me, .

a) the corret mix 100:1, 50:1 etc etc (we are currently on 50:1)
b) any idea what could be wrong, it's getting emabarrsing leaving the bearth just to be seen wading the boat back in a few minutes later

tonight i am going to start checking through,

I presume the order fuel gets to engine is
1) fuel tank
2) fuel filter
3) fuel pump
4) carb

thanks in advance,any help greatly appreiated.

 

[clent586]

Re: Yamaha 40

I have an 1984 ELN 40, probably close to the same age as yours. You are having very similar problems that I have had. I have received some great info on here. Start by getting a manual for the motor. Check to make sure your not getting air in the boat side of the fuel system. Clean tank, new filter, check fuel pump and make sure the diaphram does not have a hole in it. Does your motor not have oil injection? If so, you should not need to mix the gas/oil. Check compression (I have not done this yet by the way). I rebuilt my carbs, new fuel pump for around $100 by doing it myself. Ran about 200% better after doing that. I did the static link and sync but do not have all the tools to complete the dynamic part. This is an important step. Just by doing the above, my boat now idle great, goes into gear without stalling, I can shut it down in the middle of the lake and it actually fires up without hesitation. I have a 16'10" Bass Tracker with decks....etc... was running about 18 mph before work down but GPS yesterday showed 28 mph with me (265lb) my two kids (7 & 11) and my 60 lb lab.....two batteries and full fuel tank and a crappy prop. The work is very rewarding when it is done by yourself and also saves you a ton of cash! Good Luck

 

[99yam40]

Re: Yamaha 40

Here is a good thread on testing fuel systm

http://forums.iboats.com/showthread.php?t=283363

 

[andy_babs]

Re: Yamaha 40

Hi guys, thanks for yor hints am going to start at the tank and work through,
our fuel may be a bit stale so start there and head towards the carbs, not to keen in pullin that to bits but we will what happens, i will kee you updated.
thanks again