Need some help/advice

[petrey10]

I just bought an old 1971 Larson with a Gm inline 4 cylinder sterndrive engine that I thought was supposed to put out 140 horses. Well I wanted to test it out today after I bought it (it has been sitting for awhile but I dumped the gas tank, filed the points on the carb, and it would idle really)...Well we got it started and it would idle pretty well in neutral and then I could put the boat in gear and it wouldn't idle as well but still ran most of the time...Then I would try to put it in gear and BAM the engine would bog out...well then I put it in neutral and tried reving the engine up and it did pretty well...then put it in drive and it would bog down but the take off...but when I was at full throttle the engine would back fire and I would only be going 10-15mph...This was with the trim set all the way down ( the hydrolics work pretty well as I can raise and lower the prop at will)...I really wish I could get this baby running because there is only 185 hours on the engine and it came with all new leather and carpet for the interior and for 700 bucks was a steal...can anybody help me?? do I need to rebuild the carb?? is 15 mph the fastest this can go?? I was told the previous owner could go about 40 on it...the speedometer goes up to 65 so I would think I could hit 60 pretty easy... PLEASE HELP I am desperate...

[redtech]

40mph is most likely what it will do. if you like we can install a speedo that reads up to 100mph but 40 is going to be it,
before you touch the carb please please check dwell, then timing, carbs are the last in the list to be touched everything else has to work first