mercury 402 40hp blue band wont start

[chestercheese]

hello just wondered if some one could help me
i have a mercury 40hp 402 blue band 2stroke quite old,
i've had it running only a few times, when i've had it running it will only run for about 15mins then die, (it pumps water ok) it has a spark but just wont fire up, even if i put fuel in with the spark plugs, it has good compression, since then it dos'nt wont to know. not even a fart come out of it, i've had the carb recond'd and replace a few old wires, just cant understand why it wont go????

[9D280]

Chester,

Firstly, welcom to Ribnet!

I suspect the reason it dies after 15 mins at idle is that it has oiled itself up. I can't think of any premix 2- strokes that wouldn't.


So, assuming you have a well tuned carb, it's sparking healthily and it just won't start, the list that comes to mind is:

- Deadman in place? (not an insult- we've all done it!)
- If you replaced wires, are the cyls sparking in the right order? (i.e swap the plug leads around)
- A blueband will have good old condenser / points ignition - is your condenser gubbed?
- Not sure what carb you have on there, but if it's one of the ones that doesn't have a choke flap but the choke works an "enrichener valve", I find mine will only start from cold with that open (i.e "choked") and the throttle closed (even tho' the throttle has a "start" position that would imply you want a half open throttle).

Try that lot & let us know what happens.

[Nos4r2]

It's not points, it's Mercury's own 'thunderbolt' ignition. Depending on the year,it'll either have a belt driven 2 output distributor or (if I remember correctly)the contactless later setup that's almost the same as late '80s bike electronic ignition-sender, igniter/CDI box and coils.
If it's the latter, don't mess around with it while it's running as it sends a very high voltage to the coils. If it's the dizzy version, it's ancient and the dizzy may be impossible to work on-they are a sealed unit though some have managed to dismantle it.

Anyway, it doesn't sound like sparks are the problem unless you need new plugs,so now you need to compression test it. It should be over 100psi and within 5% on each cylinder.

The other possibilty is your reeds are gummed up or u/s. It's probably going to be bad news if they are, as the reeds are on the crank and it's simply not worth fixing them if they die.

I'd seriously think about changing the engine anyway. The 402 was awful when new and now they are awful and ancient...

[chestercheese]

hello and thanks for the advice, i think i will get another engine, i've got the chance of getting a 135hp evenrude v4, apparently work perfectly? could you let me know if these engines are any good or shall i look esle where for another? once again thanks for the advice people

[Nos4r2]

Originally Posted by chestercheese

hello and thanks for the advice, i think i will get another engine, i've got the chance of getting a 135hp evenrude v4, apparently work perfectly? could you let me know if these engines are any good or shall i look esle where for another? once again thanks for the advice people

You'd better make sure the transom won't fall off with that on it...