Crossflow - Smell of Petrol

17 posts / 0 new
Last post
saundersian
saundersian's picture
Offline
Last seen: 53 min 26 sec ago
Joined: 17/04/2014
Crossflow - Smell of Petrol

Maybe I'm becoming too sensitive, but I've noticed a distinct smell of petrol whilst driving my Crossflow (1600 Twin 40s).  Although, to a certain extent,TADTS, this seems stronger than I've noticed in the past with other Crossflows I've owned. On switching off the engine there is sometimes petrol seen in the body of the carbs when viewed through the aperture of the (removed) inspection plate to the rear of the carbs. Any thoughts or just time to replace all seals in the carbs? 

SM25T
SM25T's picture
Offline
Last seen: 59 min 24 sec ago
Joined: 17/04/2014
Check all flexible fuel hoses too. They harden and perish all too quickly.
saundersian
saundersian's picture
Offline
Last seen: 53 min 26 sec ago
Joined: 17/04/2014

SM25T. Thanks - No visible leaks/perishing of hoses.

Roger King
Roger King's picture
Offline
Last seen: 23 hours 11 min ago
Joined: 17/04/2014

First place to start is checking your float levels, the state of the needle valves and your fuel pressure.

saundersian
saundersian's picture
Offline
Last seen: 53 min 26 sec ago
Joined: 17/04/2014

Roger K - Thanks. Is it possible to give a precise ideal value (or range) for the fuel pressure. I am right in thinking if there is excess unburned petrol (causing the smell and residual petrol after switching off) then the pressure is likely to be too high???

barry watts
barry watts's picture
Offline
Last seen: 13 hours 32 min ago
Joined: 17/04/2014

I was getting a strong smell of petrol after fast cornering.  The front carb float level turned out to be a bit on the high side.

Baz.

saundersian
saundersian's picture
Offline
Last seen: 53 min 26 sec ago
Joined: 17/04/2014

Baz - Thanks. Smell is not related to cornering as occurs when driving straight and also at rest. However, perhaps float levels are an issue, which would concur with Post #4

opplock
opplock's picture
Offline
Last seen: 14 hours 53 min ago
Joined: 17/04/2014

I'd get it checked out post haste. My x/f had a Viking funeral shortly after I noticed a strong smell of petrol. Deciding that I'd check it out when I got home (8 miles away) wasn't the best idea in hindsight. 

Englishmaninwales
Englishmaninwales's picture
Offline
Last seen: 1 hour 22 min ago
Joined: 17/04/2014

Float chamber levels and condition of hoses as described above. If fitted, check the cold start mechanism on both carbs, they are a good source of petrol leaks.

Malcolm

Roger King
Roger King's picture
Offline
Last seen: 23 hours 11 min ago
Joined: 17/04/2014

Fuel pressure should be around 2psi which doesn't sound a lot, but all it needs to do is dribble fuel in at the rate it is being consumed.

Excess pressure is a more likely problem if you have an electric pump. If you have a mechanical pump, check that the diaphragm isn't split as this can cause fuel to leak into the oil: an inexplicably high oil level is sometimes also a clue that this might be happening.

OldAndrewE
OldAndrewE's picture
Offline
Last seen: 11 hours 23 min ago
Joined: 29/04/2020

If I have an electric pump with a stated pressure (on a closed outlet) of 4.26 +/- 0.4 psi feeding twin 40 Dellortos on a XFlow will that be OK or do I need to fit a regulator to reduce it?

1985 S3 1700 XFlow.  Undergoing full restoration