[amazon31]

I own (or should I say it owns me) a ‘70 145 with Dual Strombergs (featured in Rolling Magazine this issue). They were rebuilt, added Pertronix, Pertronix coil, rebuilt Bosch distributor, new plugs and wires. Cold start is fine with manual choke but hot start requires the “foot to the floor” strategy the owners manual recommends. Here is the curious part, after the hot start, it drives okay but if I have to stop shortly after the hot start it won’t idle and stalls. After a few miles without stopping, it is fine. I moved the fuel filter farther away from the block and added some insulation to the fuel line that feeds the carbs.

Yesterday, it stalled turning into my driveway and would not restart. Just cranked away and then I gave up. Yes, it has gas in the tank.

One last thing...it runs cool when driving. In 80 degree weather, if I stop and let it idle I can watch the temp gauge move quickly towards red. I haven’t let it get into the red. I put a new thermostat in but that hasn’t helped.

I acknowledge the fact that it sat for 30 years but we have taken the necessary steps to cure obvious issues like cleaning tank, fuel lines etc.

Crazy.

 

[142 Guy]

I am not much of a carburettor person; but, I know that the 1971 Strombergs have a hot start valve which deals with a too-rich fuel mix on a hot start conditions associated with high vapour pressure in the float bowl. The service manual sez "If it is to function properly, it is important that the hot start valve is accurately adjusted...…" Thing is, I don't think the factory service manual covers 'accurate adjustment'.

The 1971 Stromberg also has a temperature compensator device. If it does not function correctly it can cause idle speeds to drop (engine die?) during warm conditions. That might be something to check.

The

After a few miles without stopping, it is fine

comment almost seems like you might have vapour lock issue or high vapour pressure in the float bowls. Do your strombergs have heat shield to prevent radiant energy from the exhaust manifold and head from cooking the carbs and if so, have they gone missing? The 1971s definitely had heat shields - which looked kind of minimalist. Perhaps some heatshields with more surface area to block radiant heat might help.

Volvo engine coolant temperature goes up and down - a lot. I have a megasquirt retrofit on my B20E and I can watch on my laptop the coolant temperature as measured at the D jet sensor at the front of the head swing 10 C easily. If your coolant overflow bottle is about 2 cm above the min line when stone cold and does not reach the max line when really hot, I would not get too up tight about the temperature gauge readings. If you are venting coolant, then I would be concerned. At idle, the temperatures as measured on the dash gauge sensor (at the back of the head) are quite a bit hotter than the front of engine temperatures. 10C - 12C hotter at the back of the block would not be out of the question. This disappears once the engine speed picks up and coolant flow increases. When I am driving on the highway the front and back of head temperatures merge to within 1-2 C of one another which is probably within the sensor calibration error. If you do have a venting problem, then I suggest a trip to a good rad shop to have your rad cleaned out and pressure tested. I discovered that the bottom 25- 30% of my 1971 crossflow was plugged contributing to temperature problems on hot days.

 

[mathue]

Congats on the car BTW, my first car was a 1970 145S.

Anyway, it certainly sounds like an over rich behavior.

I had a similar issue and sadly I don't recall the exact issue any longer, however my addled brain seems to think we eventually found an issue with vapor collection.

142 Guy also has good suggestions as well. I find their suggestions are usually dead on.