Reply
 
Thread Tools Search this Thread
 
Old 30 March 2014, 17:55   #11
Member
 
A1an's Avatar
 
Country: UK - Scotland
Town: Fort William
Make: Humber Destroyer
Length: 5m +
Engine: Yamaha F80
Join Date: Mar 2012
Posts: 2,239
RIBase
Quote:
Originally Posted by bartiny View Post

If that was the case then the engine would not run after the carb bowl had emptied as the pump would not work.

But for what it is I suppose its worth checking.
I had EXACTLY the same thing on a Yam 75AET, it would supply enough fuel to the carbs but small amounts were being sucked into the crankcase through the pumps vacuum port.
__________________

__________________
There is a place on this planet for all of Gods creatures.........right next to my tatties and gravy.
A1an is online now   Reply With Quote
Old 30 March 2014, 18:00   #12
Member
 
simon23's Avatar
 
Country: UK - England
Town: liverpool
Make: tohatsu6.1 one desig
Length: 6m +
Engine: mariner 125hp
Join Date: Jan 2012
Posts: 357
I don't want to put a downer on you, but it wasn't running right before you 'broke' it.i spent weekend after weekend messing around saying I'm sure its something simple and getting no where.if you can get the cash together give it to the man who knows,pay him and enjoy your boating.
__________________

__________________
simon23 is offline   Reply With Quote
Old 30 March 2014, 18:22   #13
Member
 
Country: UK - England
Town: Warrington
Boat name: Boat
Make: Zodiac
Length: 3m +
Engine: Yam 28hp
Join Date: Mar 2014
Posts: 8
well - I risked divorce and nipped out the the shed to see my nemesis once more

I whipped out a size 9 wrench and took off the fuel filter

I can confirm that if you blow into it , air comes out of the side closest to the engine. I take it that it has a hole that shouldnt be there

The engine did struggle to run when idling I had to speed up the idle a few turns to keep it going - im thinking it must just be a small hole....

if this is it , i will get some diaphrams from ebay or some where and replace -

Muchos Gracias everyone - you are outboard gurus
Attached Thumbnails
Click image for larger version

Name:	IMG_20140330_231447.jpg
Views:	75
Size:	51.4 KB
ID:	92853  
__________________
gtturbo is offline   Reply With Quote
Old 30 March 2014, 18:43   #14
Member
 
Country: UK - England
Town: Warrington
Boat name: Boat
Make: Zodiac
Length: 3m +
Engine: Yam 28hp
Join Date: Mar 2014
Posts: 8
I would usually take it somewhere - but............ this thing is old old , its a relic - about the same ages as me , 1978 era

I want to know a bit more about it myself , just so I feel confident if something daft happens I know what to check etc.

The fuel diaphram is defo split as per picture - the pump itself if coroded and a screw is seized so im going to replace the unit.

Obviously this may well lead me back to square one with a bad cold start.....but thats not too bad.... it does start just makes hard work of it....

maybe with the new pump and a carb clean , a bit of practice i will get a quicker less time consuming start..........
Attached Thumbnails
Click image for larger version

Name:	IMG_20140330_233501.jpg
Views:	86
Size:	62.1 KB
ID:	92854  
__________________
gtturbo is offline   Reply With Quote
Old 31 March 2014, 02:46   #15
Member
 
A1an's Avatar
 
Country: UK - Scotland
Town: Fort William
Make: Humber Destroyer
Length: 5m +
Engine: Yamaha F80
Join Date: Mar 2012
Posts: 2,239
RIBase
That's your problem right there.


I actually have a couple of those skins on my spares shelf just incase, I would offer to send you one but you are going to need a whole new pump by the sound of it.

Don't be so hard on the bulb next time
__________________
There is a place on this planet for all of Gods creatures.........right next to my tatties and gravy.
A1an is online now   Reply With Quote
Old 31 March 2014, 05:23   #16
Member
 
Country: UK - England
Town: Warrington
Boat name: Boat
Make: Zodiac
Length: 3m +
Engine: Yam 28hp
Join Date: Mar 2014
Posts: 8
Thank A1an. I have ordered a pump and hopefully it will be here by Wed.
Thanks for the advice , I would certainly not have known to check that , but I will in future.
__________________
gtturbo is offline   Reply With Quote
Old 31 March 2014, 14:54   #17
Member
 
Country: UK - Scotland
Town: north ayrshire
Boat name: charlie girl
Make: reiver 3.8/regal3760
Length: 10m +
Engine: 40hp 2st 2x6lp 315
Join Date: Jul 2009
Posts: 1,494
If its any conciliation I had a 28hp yam a few years ago & it was a cracking little engine when it was going so probably worth persevering with
I also had a pump diaphragm fail on an 85 yam & it ran fine at high rpm but was rough at tickover which sounds a bit like the fault you have
so sounds like your on the right track
__________________
beamishken is offline   Reply With Quote
Old 31 March 2014, 15:04   #18
Member
 
simon23's Avatar
 
Country: UK - England
Town: liverpool
Make: tohatsu6.1 one desig
Length: 6m +
Engine: mariner 125hp
Join Date: Jan 2012
Posts: 357
I had a couple of 28e's think they may be the same as yours but with electric start, same as above great motor ,only downside was quoted 35 for a set of points from the mariner dealer, luckily didn't have any in Stock. Got some from the yamaha dealer for the bargain price of 13 per set! !!
__________________
simon23 is offline   Reply With Quote
Old 31 March 2014, 15:05   #19
Member
 
RIB-Teccie's Avatar
 
Country: UK - England
Town: Leeds
Make: Valiant 450
Length: 4m +
Engine: Yamaha 55HP
Join Date: Jan 2013
Posts: 448
If you have ordered a fuel pump you will probably need the gasket between it and the block.

Couple of tips.

1. Remove fuel pump pipe going to carbs. Place finger over it. Squeeze bulb. If you can still prime the bulb (assuming it is in good condition) the chances are the diaphragm is holed. To make sure, repeat test with pump removed and if fuel squirts out if the middle hole it's definitely holed.

2. Attach fuel line directly to carb and squeeze bulb, of the fuel squirts out of the carb breather or out if the carb air intake, your float is set too high or the needle valve us worn or stuck open.

The 28a is a super engine. It's bad points were the bottom crank seal and bad corrosion problems where the water pump attaches to the gearbox. The condenser can play up also.
__________________
RIB-Teccie is offline   Reply With Quote
Old 02 April 2014, 08:43   #20
Member
 
Country: UK - Scotland
Boat name: Wildheart
Make: Humber/Delta Seasafe
Length: 5m +
Engine: Merc 60 Clamshell
MMSI: 235068449
Join Date: Apr 2007
Posts: 4,610
While you are getting spares - a set of new spark plugs can make a huge difference to the running.

The fact you have unburnt fuel in your bin might hint that one cyl is acting more like a premix pump than a power source.



I had similar with an old 55 of similar vintage to yours. After I changed the plugs (& as it turns out the HT leads) I gave them to a spark mate to see what his Megger thought - one of them would have failed a PAT test!
__________________

__________________
9D280 is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off





Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -5. The time now is 08:27.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.