Honda B75 ca1976 Cowling Prob?

apshutt · 29 May 2013, 19:36

I have the above engine which is running fine with the cowling OFF. But as soon as the cowling starts to go down from front to back the engine starts to run sluggish!!!!!!!!!! The cowling is nowhere near the ht leads or the fuel pipes when this happens and is also clear of the "STOP" button. I am baffled........any ideas???

Thanks in advance

Andy

captnjack · 29 May 2013, 19:45

not familar with this vintage, but is it somehow blocking intake air?

apshutt · 29 May 2013, 19:52

I thought that too but it's also clear (I even turned the intake round, to no avail). But thanks Capt.

High regards
Andy

Nos4r2 · 29 May 2013, 20:26

Exhaust gasket leak at a guess. It'll be choking in it's own exhaust gas.

apshutt · 29 May 2013, 20:31

Thanks for that Nos4r2, that sounds very very feasable, all I need to do now is find out where that is

Too late tonight so I will have a gander at that tomorroe, thanks again

High regards

Andy

Nos4r2 · 29 May 2013, 20:41

That's where it gets painful-it might be leaking where the powerhead bolts to the leg, which is a powerhead off job.

You might find the leak the same way you leak detect on tubes with fairy liquid, but if you try it, make sure you rinse it well afterwards as there's a lot of salt in washing up liquid.

apshutt · 29 May 2013, 21:27

I did spill some oil in the lower cowling so maybe that is causing a problem when it's burning off as you mentioned. I will give it a good clean and check the gasket out as you suggested.

Admirations and thanks

Nos4r2 · 29 May 2013, 21:31

I might be wrong yet!

If there's oil down there, it won't burn off that much-the motor doesn't get that hot-so if you're seeing smoke, you've got a gasket leak.

apshutt · 29 May 2013, 21:39

I bow to your experience sir, and will check the gaskets. Can I check for "blowing" on the leg where it joins the motor?

Andy

Nos4r2 · 29 May 2013, 23:39

If the gases are getting into the cowling, you should be able to see it somehow.

m chappelow · 30 May 2013, 07:21

Any chance the cowling has any saltwater residue on the inside that's causing a plug lead to short out , it doesn't have to be touching ( had that with an old Yamaha)

Other than a blocked air intake or somethings getting trapped as Nos says a leaking exhaust gasket
just wondering if your running the engine on muffs & hose or is it in a tank of water as if its in water it should make the condition worse .

apshutt · 30 May 2013, 09:29

Thank you. I am planning to get it out at about 12:00 today. Watch this space, as they say.

High regards

Andy

apshutt · 30 May 2013, 09:35

When I put the cowling on it is only at 45 deg when it starts misfiring. Which is about 4" away from the ht leads, Thanks for that though as I do run it in a water butt.

Blessings

Andy

apshutt · 30 May 2013, 13:07

There is an "inspection?" hole near the top of the leg. I took the cover off and with the vacuum cleaner on blow it runs fine so I am now convinced it is the exhaust gasket which Nos4r2 suggested.Thanks Nos4r2, and thank you to you all tto for giving me some ideas in solving the prob out.
All I have to do now is work out how to take the leg off

)
I do have an "online" manual but it'snot too clear. So fingers crossed for me please and if you are a Christian like me prayers would be well accepted.
Thank you all and I will keep you updated.

High Regards and blessings to you all

Andy

apshutt · 30 May 2013, 17:31

So far got the "leg" off and 7 out of 8 bolts that hold the engine in.

Guess what though? Nope not stuggling getting numbr 8 out, just cant find it

)

Andy

Nos4r2 · 30 May 2013, 17:47

Ouch, afraid I can't help on that one.

Have you dropped the gearbox off? It'll make removing and refitting the powerhead a bit easier.

apshutt · 30 May 2013, 17:56

Hi Nos4rs got everything the manual tells me to, 4 bolts on the underside of the lower cowling/tray, 3 up under the engine around the drive shaft. But the last one it says Unscrew using a universal wrench after the oil case grommit is removed" But I cant seem to find it.
I will have another go tomorrow evening it's been a stop start day today

Respect and thanks Nos4r2

Andy

apshutt · 30 May 2013, 18:09

I think I may have found it,I think it's somewhere through that bung I was blowing air through earlier. But as the engine has been put to bed I wont know for sure till tomorrow.

Thanks all and blessings

Andy

apshutt · 31 May 2013, 20:42

Hi all and especially Nos4r2,

It's not the exhaust gasket after all. I found that bolt and it was in an almost impossible place to access but finally got it out

) BUT don't know how on earth I will get it back in :+(
So what was the problem if the gasket was ok? I was that the exhaust had rusted through

( so I will see if I can get one made locally, as none on Ebay.

Regards to all
Andy

apshutt · 31 May 2013, 20:47

Anybody out there know where I can get one?

Andy