Alfie Posted February 20, 2016 Share Posted February 20, 2016 Been having problems with a pair of overhauled 150 strombergs, engine starts ok with the choke and warms up but if the engine stalls with the engine hot and you try to restart again petrol pours out of the front carb from a hole on the filter mount flange face. Ive included a photo showing the hole the petrol pours out of. Ive also fitted a new mechanical fuel pump and a filter king. All petrol pipes are brand new.Can any one suggest what the problem is. One thought is to reduce the fuel pressure by the filter king but my line of thought is that if it is a high fuel pressure then why only one carb flooding. Quote Link to comment Share on other sites More sharing options...
Nick Jones Posted February 20, 2016 Share Posted February 20, 2016 That is the float chamber over flow passage. so the needle valve in that carb is not shutting off.Fuel pressure may be too high (common problem with repro pumps available today), perhaps made worse by a needle valve issue or slightly different float heights which causes one to give way first. If your Filter King includes the regulator function, I'd begin by turning it down. IIRC 2 - 2.5 psi is correct.Nick Quote Link to comment Share on other sites More sharing options...
thebrookster Posted February 21, 2016 Share Posted February 21, 2016 As Nick says, Needle valve is not closing properly.From my experience this can be caused by two options, High Fuel pressure would be a third.1) Floats not operating correctly. I had one carb where the post for the float had sheared, causing the float to jam. I also on one occasion managed to fit the pin for the floats the wrong way, allowing the pin to come loose and again jam the float. This was on an early set of CD150's, yours are later versions so I suspect my two failures won't affect you, but you may have another float related issue!2) Rubber sliver caught in needle valve!! I found that this can cause either (or both) of two issues, one is not enough fuel getting to carb in the first place causing fuel starvation on engine, the other is if the rubber gets into the needle valve it can cause it too jam open.Also, if it is a new needle valve then quality may not be brilliant, so it might be that the valve is simply sticking for no real reason. This tends to fix itself over time, however if you give the side of the carb a quick thump when it is overflowing chances are it will stop if that is the cause (basically jar the valve and allow the float to close it properly).Cheers,Phil Quote Link to comment Share on other sites More sharing options...
don cook1 Posted February 21, 2016 Share Posted February 21, 2016 Float heights have to be checked/adjusted with the carbs upside down. measure 18mm from top of float (resting gently on the needle valve) to the flange, gasket removed. You can't do it with the carbs attached as you would have to hold up the floats to close the needle valve and, unless you have super-sensitive touch, you will get a distorted measurement. I'd agree with everyone else about the needle valve and/or it's seating. Quote Link to comment Share on other sites More sharing options...
Pete Lewis Posted February 21, 2016 Share Posted February 21, 2016 http://www.buckeyetriumphs.org/technical/technical.htm good for clues on float fittingAs said rubber slivers are devils, especially as you have been refiiting hoses and pipesthe bundy cut a small sliver off the inside of the hose when inserting and it floats aboutsome later floats have two valve arms and the floats will fit upside downtheres some good pics on the huckeye site , Quote Link to comment Share on other sites More sharing options...
Alfie Posted March 12, 2016 Author Share Posted March 12, 2016 Thanks Guys, checked the float chambers for deb re etc but nothing found so turned the regulator down on the filter king however the engine still will not start when hot but is not flooding now. The symptoms are engine starts with choke when cold and idles, pulls away ok but once up to temperature with the electric cooling fans working and i pull away then stop lifting off the throttle the engines dies and wont start again, if i gently touch the throttle the engine does not stall. There's a smell of petrol out of the exhaust when turning the engine over after it stalls which suggests cylinders have a supply of petrol.The carbs have been refurbished with a full build kit including butterfly valves, the ignition is a brand new electronic system with new plugs leads and dizzy, the engine has been fully overhauled also. One thing ive not done is check the fuel mixture with a gunson colour tune.Any advice as to what may be the problem. Quote Link to comment Share on other sites More sharing options...
Alfie Posted March 13, 2016 Author Share Posted March 13, 2016 Ok i think i may of found the problem, i think the fuel is vaporizing due to the heat build up in the intake manifold. Ive got a stainless manifold which i am going to wrap in heat tape to see if that cures the none starting problem. Today after the engine was stopped then tried to restart unsuccessfully i let the engine cool for half an hour at which point it started, i removed the plugs after the attempted restart to check if they were dry which they were so no fuel getting to the cylinders when hot. Quote Link to comment Share on other sites More sharing options...
Jonny-Jimbo Posted March 14, 2016 Share Posted March 14, 2016 Yeah, sounds like fuel vaporisation. My Dad had that issue on his Lotus Elan, which also had an unwrapped tubular exhaust. When he stopped for fuel after a drive he had to pop the bonnet to let the heat out or it would boil the fuel in the carbs and not restart! Quote Link to comment Share on other sites More sharing options...
Alfie Posted March 23, 2016 Author Share Posted March 23, 2016 Ok so i have wrapped the exhaust manifold and the engine still refuses to start when hot. I have at the moment sainsubury's unleaded petrol in the tank which i assume contains ethanol so my next question is anybody using a standard unleaded mix that contains either 5% or 10% ethanol without any problems OR do you tend to run on one of the main suppliers super unleaded mix which i have been informed is ethanol free at the moment. Ive not ran the car on the road so do not have any previous experience with this engine. Quote Link to comment Share on other sites More sharing options...
Richard B Posted March 23, 2016 Share Posted March 23, 2016 I would go for Super-Unleaded. Triumphs were designed for 4 or 5 Star petrol. Cheapo unleaded is the equivilent of 2 Star.However, are you sure it is not an ignition problem? I have have coils and condensers misbehave when the engine is hot. I've also had the gently on the throttle works, foot down stalls and it was a small wire in the distributor breaking down.Putting your foot down means more petrol and air going, requiring a stronger spark to bridge the gap of the spark plug. Quote Link to comment Share on other sites More sharing options...
thescrapman Posted March 23, 2016 Share Posted March 23, 2016 I have always been lead to beleive that Super Unleaded derives it enhanced octane rating from teh use of Ethanol.And E10 is a definate No-No for a TriumphE5 is tolerable.CheersColin Quote Link to comment Share on other sites More sharing options...
Pete Lewis Posted March 23, 2016 Share Posted March 23, 2016 Well I used 97 ron in the vit6 for years without a single problemshe had an un wrapped 631 heat shield under the carbs , and a engine driven fan and std air box with waste pipe tubes to the front she could idle for an hour without a hic up.You do need to keep an airflow under the bonnet and a cold air supply to the carbs as triumph designed you just dont get that with a electric fan. You get excessive under bonnet temperaturespete Quote Link to comment Share on other sites More sharing options...
Jonny-Jimbo Posted March 24, 2016 Share Posted March 24, 2016 Hmm, that could explain why my 2000 is running on, even with the electric fan keeping the radiator cool.Also, something worth looking into is Tetraboost. It's nasty, nasty stuff, contains lead. BUT it's the only way to make your fuel genuinely leaded again, can be used as an octane booster too AND protects against the effects of ethanol and the water build up that occurs. Never open a bottle indoors - even in a garage with the door open. It's bad stuff for you BUT great for your car! http://tetraboost.com/ Quote Link to comment Share on other sites More sharing options...
.thumb.jpeg.b15b81ef10abeea1c3039ae03c4a9f3a.jpeg)
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.