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Hard to start if it sits for more than a few hours

Posted: Fri May 10, 2019 1:08 am
by adrenalinsports
Wondering if any of you can give me some advice? I have a Volvo that runs really well. But if it sits for a few hours or especially overnight it takes forever for it to start. Seems like the fuel drains out of the lines and it has to wait 3 minutes or so for the fuel to get back to the motor. As soon as it does it fires right up. Then after that it will continue to start very quickly unless i let it sit for a few hours. Anyone have any ideas to fix this?

Thanks,

Jud

Re: Hard to start if it sits for more than a few hours

Posted: Fri May 10, 2019 11:10 am
by brandonium
What are you seeing at the gates fuel filter at the front of the engine? Is there fuel in it or is that also empty?

Re: Hard to start if it sits for more than a few hours

Posted: Fri May 10, 2019 7:19 pm
by adrenalinsports
There is still fuel in the filter. Fuel is also present in the Zenith carb bowls. Like the choke circuit is not passing fuel.

Re: Hard to start if it sits for more than a few hours

Posted: Sat May 11, 2019 12:35 pm
by one2many
adrenalinsports wrote:
Fri May 10, 2019 7:19 pm
There is still fuel in the filter. Fuel is also present in the Zenith carb bowls. Like the choke circuit is not passing fuel.
Zenith carbs??? On a Volvo! are you sure?

Once the carb bowls are full fuel can't drain back out, it's only ways out are through the intake system or if left sitting it could evaporate making for slow initial start ups. If you still have the original mechanical pump it may benefit from a rebuild kit. The diaphragm may be worn making for inadequate pressure and non return valve may be letting fuel drain past, this would make for a slow start as you wait for both fuel pressure and volume to build up. Electric pump retro fit is an excellent and simple option if going away from stock doesn't worry you, only be sure pump pressure doesn't exceed carb spec. A few things to look at first though are- check for vacuum leaks, loose/leaking carb mount to intake and proper venting of system....float bowls and tank cap, it might be something that simple. Failing that, lastly I'd give the carb castings a really good clean and put a kit through them. Before you pull it completely down check for any loose "brass" fittings, an improperly seated emulsion tube, Venturi or jet of any kind (idle,primary/secondary) can cause a problem like your describing but otherwise work pretty well for the most part.
The other angle to consider is valve clearances. Even slightly tight valve clearances on EX or IN will make any engine a slow starter then eventually a "tow start" is the only way to start it. A Slightly open valve will drastically reduce compression making fuel ignition difficult. Unfortunately this is pretty common with the stock B30 head as modern unleaded fuels offers no protection to the valves or valve seat, the result is valve seat recession into the head then the valve will not seal on its seat properly...this problem is generally worse when the engine is warmed up, as metal expands the tolerance of such clearances get even smaller
Hope this helps, diagnosis from a distance can be difficult

Re: Hard to start if it sits for more than a few hours

Posted: Sat May 11, 2019 9:52 pm
by adrenalinsports
Our mechanic figured it out. The choke plate was in upside down. Not sure if it’s called a plate but something in the carburetor that activates the choke was upside down. Starts easy now.

Re: Hard to start if it sits for more than a few hours

Posted: Sun May 12, 2019 2:54 am
by pinzi
Stromberg carbs?

Re: Hard to start if it sits for more than a few hours

Posted: Sun May 12, 2019 7:27 pm
by Jim Molloy
Zenith? Yes.
Stromberg? Yes.

Zenith-Stromberg 175 CD 2 SE

Hope this helps.

Jim Molloy
Waldersee Farm
http://www.northwestmogfest.com

Re: Hard to start if it sits for more than a few hours

Posted: Mon May 13, 2019 6:01 am
by one2many
Jim Molloy wrote:
Sun May 12, 2019 7:27 pm
Zenith? Yes.
Stromberg? Yes.

Zenith-Stromberg 175 CD 2 SE

Hope this helps.
I had a sneaking suspicion this was technically the case.