Suzuki DF140 problems

jlanng · 28 November 2004, 20:51

Well, it didn't take long for a problem to occur

We recently purchased a Ribtec 585 with a Suzuki DF140 motor.

We launched (for the first time!) at Mudeford on Saturday. Lovely weather in the morning, and the sea was very calm. It took a while to start, but it seemed to work much better once I'd plugged the kill-switch in

Our first impressions were that the engine was very quiet and the sea was too flat for any real hull testing

But for some reason it wouldn't rev past 5000. It felt fine and picked up very nicely at every speed under 5000. I thought it might have been throttle cable slipping somehow, and didn't worry too much more about it. After that however, every time we depowered and repowered, the maximum revs achieved dropped by about 500rpm a time! It felt very much like a slipping cable, so we turned back straight away. By the time we were back at Christchurch she was only revving to 2000rpm - we couldn't even got up on a plane! Intererestingly, if I increased the throttle quickly, it would cut straight down, but I was able to tease the revs up by moving the throttle very gently - this all pointed to a slipping cable.

When we got it home, I connected the flush muffs and it revved just fine - but then it wasn't under any load. I found the throttle under the hood and it looks like the controls *were* in fact fully opening the throttle. Either that, or somehow it had started working again on the way home.

No engine faults showed up at any point. If it was a fuel supply problem, I'm guessing the lambda sensor would read lean and throw up a fault?

Any ideas what might cause this? I'm going to get on the phone tomorrow, as it should still be under warranty - but the original supplying dealer is hundreds of miles away, it if it's something obvious I'd like to have a crack at it myself!

ADS · 28 November 2004, 21:08

I may be way off here but my mates 'rude 90 Etec's controls were rubbing on the cowling and they tended to stick. On an engine like that its more likely to be a mechanical fault than anything else.

tonka · 28 November 2004, 21:45

it sounds more like shortage of fuel hence the reason for running fine when not under load,or poss drawing air from somewhere.had same problem on yam 85 years ago.

gingercoastie · 28 November 2004, 22:09

Quote:

Originally Posted by tonka

had same problem on yam 85 years ago.

Wow, thats a long time

Nasher · 28 November 2004, 22:37

Sounds like fuel to me too.

Had the boat/engine been laid up for a while? and have you checked the fuel filter for Cr*p, or water if it has a seperator? Moving the Boat around after a lay-up may have disturbed some silt etc in the tank or there may have been a build up of condensation.

Its a shame that your first trip out was ruined.

Nasher

PS - Have to agree 85 years is a long time ago to have been running a Yam. Japs must have invented Outboards afterall.

Cookee · 29 November 2004, 09:48

Have a look at the bush in the prop as well - you never know!

Wayne Rogers · 29 November 2004, 20:29

I would have a look at the breather on the fuel tank to see if it is working properly. A good way of testing it when the problem is there is release the fuel filler cap and see if the revs pickup. If it is that it could damage the tank if not sorted.

Hightower · 30 November 2004, 01:12

You say you forgot to fit the kill cord, so is it percevable that you also forgot the vent screw on top of the fuel tank as well, it happens!!

Jono Garton · 30 November 2004, 08:13

I would also suggest fuel shortage. Could be the inner of the fuel pipe breaking down. When your going along get someone to prime the fuel primer and see if it is any better, also look at whats happening to the fuel primer, is it hard, soft or clapsed. Fuel primers are often the first thing to go on a fuel system, is it cracked anywhere?

The problem is probably alot more simple than you think.

Jonny Fuller · 30 November 2004, 09:04

Quote:

Originally Posted by Cookee

Have a look at the bush in the prop as well - you never know!

Prop bush sliping, causing the revs to die! I wouldn't think so.

Cookee · 30 November 2004, 09:22

Quote:

Originally Posted by Jonny Fuller

Prop bush sliping, causing the revs to die! I wouldn't think so.

OOOOOPS - the tank vent seems like a better idea!

jlanng · 30 November 2004, 10:14

Thanks guys, you've given me some excellent suggestions to go on!

The boat is fitted with a 100l underfloor tank - should I really have had to open a vent manually as with the smaller jerry can tanks? I should have opened the filler cap to see if there was a big vacuum causing the problem. Checking the primer bulb would also have been very sensible. You live and learn

Nick Hearne · 30 November 2004, 10:26

Quote:

Originally Posted by jlanng

Thanks guys, you've given me some excellent suggestions to go on!

The boat is fitted with a 100l underfloor tank - should I really have had to open a vent manually as with the smaller jerry can tanks? I should have opened the filler cap to see if there was a big vacuum causing the problem. Checking the primer bulb would also have been very sensible. You live and learn

No the tank will be self venting!
Nick

MeMe · 30 November 2004, 10:54

......considering I also run the same engine. Good luck with your inverstgations, however, if still under warranty, please make sure you don't invalidate this by "having a crack at it youself".

slimtim · 30 November 2004, 11:08

Quote:

Originally Posted by Nick Hearne

No the tank will be self venting!
Nick

Are they not always open though? I can see what jlanng is saying, surely you wouldn't have to unscrew a vent on a large in built fuel tank?

Does sound like a fuel problem. My little yamaha did that when I met up with everyone for the first under 5m IOW cruise. It wouldn't go to nearly full power so I switched the tanks over and it was fine. When I got home I took the thingy out of the tank and made sure it was all clear and its been fine ever since.

Tim

Nick Hearne · 30 November 2004, 11:22

Quote:

Originally Posted by slimtim

Are they not always open though? I can see what jlanng is saying, surely you wouldn't have to unscrew a vent on a large in built fuel tank?

Does sound like a fuel problem. My little yamaha did that when I met up with everyone for the first under 5m IOW cruise. It wouldn't go to nearly full power so I switched the tanks over and it was fine. When I got home I took the thingy out of the tank and made sure it was all clear and its been fine ever since.

Tim

Tim, yes that is what I'm saying the tank is self venting, you can not shut it off! It has a permanent open vent.
Nick

Hightower · 30 November 2004, 12:43

Still it is worth investigating the vent! could be the tube inside the console or where ever your fuel tank is located is kinked or blocked. Just eliminates another potential problem me thinks.

Nick Hearne · 30 November 2004, 12:49

Quote:

Originally Posted by Hightower

Still it is worth investigating the vent! could be the tube inside the console or where ever your fuel tank is located is kinked or blocked. Just eliminates another potential problem me thinks.

Yep, agreed may be somein livein down it!

Hightower · 30 November 2004, 12:57

Have to be something pretty stoned to be living and sucking on dem gasoline fumes.

Nick Hearne · 30 November 2004, 13:17

Quote:

Originally Posted by Hightower

Have to be something pretty stoned to be living and sucking on dem gasoline fumes.

Mite be one of doose Gas junkie's!