I repowered my boat this year with a used (1992?) Mercruiser 350 Mag 4bbl carb (not sure what brand carb, boat not here to look at). It runs great when warm and starts in neutral with a touch if it's been run recently, like sitting on the water for lunch or between tubers. When warm, it idles around 600 rpm on my tach. So, the only problem is cold starts.
Cold start, I use the same technique I used for my 1985 305 which started great: I give it two full throttle shots then leave it around 1/3 throttle. It seems to start briefly then conks out almost immediately. After this, the only way it will start is full throttle with a VOOM then I quickly trottle back to 1000-1200 rpm. Any less and it conks out again - in neutral it goes down to 400 rpm, sputters and dies. There is blackish smoke coming out when it starts this way also. Only after many minutes can I put it in neutral to idle.
One mechanic just wired open the choke and I ran itlike that for a month or so, but it still didn't start great, maybe it did warm up a bit faster. I recently unwired it and replaced the spring that controls the choke, based on it's temperature I assume. The old one was pretty rusty looking so i assumed it was the culprit. No noticeable improvement, unfortunately. This spring control does not look adjustable to me - is it? The links to the choke plate seem to move freely.
The carb has been rebuilt so i assume it's woking fine. I see shots of gas going into the carb when I advance the throttle, so that seems to be OK. The engine runs fine when warm. Any ideas what to chack first? Is it bad for the engine to be started the way I am currently (I remember sometimes using the same procedure for my dad's 1980 Impalla with the same engine)?
Thanks.
Cold start, I use the same technique I used for my 1985 305 which started great: I give it two full throttle shots then leave it around 1/3 throttle. It seems to start briefly then conks out almost immediately. After this, the only way it will start is full throttle with a VOOM then I quickly trottle back to 1000-1200 rpm. Any less and it conks out again - in neutral it goes down to 400 rpm, sputters and dies. There is blackish smoke coming out when it starts this way also. Only after many minutes can I put it in neutral to idle.
One mechanic just wired open the choke and I ran itlike that for a month or so, but it still didn't start great, maybe it did warm up a bit faster. I recently unwired it and replaced the spring that controls the choke, based on it's temperature I assume. The old one was pretty rusty looking so i assumed it was the culprit. No noticeable improvement, unfortunately. This spring control does not look adjustable to me - is it? The links to the choke plate seem to move freely.
The carb has been rebuilt so i assume it's woking fine. I see shots of gas going into the carb when I advance the throttle, so that seems to be OK. The engine runs fine when warm. Any ideas what to chack first? Is it bad for the engine to be started the way I am currently (I remember sometimes using the same procedure for my dad's 1980 Impalla with the same engine)?
Thanks.
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