motor problems

[inspired]

Just wondering has any one had the experience of a motor running well with the cowl off but once the cowl goes on the engine starts to die and cuts out
motor is a 60hp evinrude 1980

regards Jeff :-? :-? :-?

[inspired]

hi griz thanks for that breather seems clear carbies clean it really has me baffled

[Roughasguts]

Very strange and pretty un likely the motor will run rough just cause the cowl is on.

Have you looked inside the cowl, is there any sound deadoning comming away and fowling your choke linkages as you put the cowl on.

[Brumby]

Hi inspired

came across a similar one on an old Yamaha, after much headscratching and bad language we eventually figured out that the plug leads were past their best. Cover off, no pressure on lead and ran fine - cover on, leads bent over slightly to fit and motor missed and died.

Hope that helps

[blaze]

That would be my thoughts that something is touching when the cover goes on
cheers
blaze

[marshy]

Also check for an exhaust leak from the exhaust side plate or between the power head & leg.

Marshy

[FNQCairns]

It's possibly fuel, float level too high as a last check or minor flooding due to aneedle and seat? These motors are designed to run with the induction cover/baffle in place as well as the hood only then do they run at spec assuming everything else is in spec. It's hard to tell without hearing how it conks.

For instance a motor run at high revs with the cowling off creats a lean condition then with the baffle off also and it is a recipie for a rebuild.

The motor idles on the low speed jets only, too lean and they will sneeze (does yours?), too rich and they will load up (does yours?), engine temperature at the time plays a part also.

It's a pain (and depending on what it sounds like when it dies)but back (or up) each idle air screw off 1/8 of a turn then test then do it again etc until it smooths out
This really should be done in gear on the water (or test tank)as a best case, on the muffs the engine runs relativly lean due to a lack of leg water level backpressure.

A good decarbon may help, but it depends on what is up with the engine.

Another place to look is the carb sync, if that is out it can play havoc with the idle timeing and it ends up a bit of a syncronisation mess most apparent at idle.

Hope I have given you somewhere go for a look, good luck.

cheers fnq

[Roughasguts]

That's Deep FNQ, but you could be on the money there.
It's Gonn'a be a bastard to get right then.

[FNQCairns]

Dunno about that Gut's, but the first step is to listen to how it conks, like turning the ign key of therefore electrical like said above, a slower heavy rundown and possibly over rich, sneezing before it conks then restriction/lean.

It's always interesting to hear the end results, desktop guesses are just that -guesses at best!

cheers

[GBC]

I had a '55 rude which had the same prob. Turned out to be a hole in the exhaust pipe.

Looking at the above posts it could be any bloody thing though.


C.J.

[inspired]

Thanks all for your thoughts. Today started at the carbies cleaned and all jets blown out has preset mixture and idle made sure linkages are ok again runs good cowl off but not when on. Yes have checked leads ok and cowl not fowling choke thanks for that.But i have noticed exhaust leak in the bowels of th engine. Could this be my problem ??? I think exhaust gases are faulting running of engine i will look into it further in a few more days thanks every one for your thoughts will keep u posted regards Jeff

[ryank]

hi mate. it sounds like u have an exhaust leak somewhere. most probably eaten out in in the powerhead or trunk.

[marshy]

jeff , fix the exhaust leak & you will fix the running fault.The exhaust gas is causing the fault when the cowl is on , when the cowl is off is off the carbs are getting clean air.

Marshy.

[inspired]

Hi all spent a lot of time the last few nights dropped the leg looked up the exhaust pipe and found the biggist hole in the pipe at the top stripped all down broke every bloody bolt i touched but had to strip.Ok now found problem now have to find a part extract all brocken bolts new gaskets and x fingers all goes back together. Or just buy a new out board. Will let you know how it goes regards Jeff

[inspired]

Hi All
prob solved 75hp merc new will replace old 60hp should go well
jeff