Popular Post clemson_tiger29678 Posted November 17, 2014 Popular Post Share Posted November 17, 2014 So, I've wanted a B61 for quite some time and never could pull the trigger on a big rig, until yesterday! Bought a 1961 that is in super shape, no rust, needs paint...engine and trans has been changed to a 70's Detroit 6-71 and a 13 speed (NO TWIN STICK!!!!). Anyway, had a 2 hour trip to take the truck on to get it home, and had some issues. First 30min, ran great...interstate speed was 50'ish as we were getting use to it...then it started to lose power/pull. Pulled over, it was running and idling fine, looked it over, jumped back in, got back up to speed and then start losing power again. After several times of this, I pulled over, but it off, looked it over, cranked it back up and took off...ran great for 5 miles, then same issue. I learned that cutting it off for 30-45sec would get me 3-5 miles of strong running before I had to pull over and cut it off again. When I say, lost power, I mean, 10mph max up a hill...no power. To preface all of this...the truck had been in the previous owners possession for 15 years. It ran great, shifts good, brakes good...but hasn't had much maintence over 15 years. My first thought is trash in the fuel filter on the Detroit Diesel...and to put a new filter and new air filter on it. I'm open to any other suggestions. Thanks guys. Looking fwd to being apart of the Mack community. 4 Quote Link to comment Share on other sites More sharing options...
Freightrain Posted November 17, 2014 Share Posted November 17, 2014 Welcome aboard. Yup, put some new filters on it. It sounds just like my truck after I bought it. Ran fine around town, the first short jaunt up the highway and it would start to cough and sputter. I "assumed" the maintenance had been kept up from the towing company. Not so much. The filter was near clogged shut with slime and crap. Once fixed, it has purred for 13 yrs now. 1 Quote Larry 1959 B61 Liv'n Large...................... Charter member of the "MACK PACK" Link to comment Share on other sites More sharing options...
mrsmackpaul Posted November 17, 2014 Share Posted November 17, 2014 welcome mate I reckon your onto the problem the fuel filter I dont think the air filter will be the problem and you will be glad you dont have a twin stick trust me they might look the part but what you have is much easier to drive shame about the GM though at least you wont fall asleep LOLPaul Quote Link to comment Share on other sites More sharing options...
thomastractorsvc Posted November 17, 2014 Share Posted November 17, 2014 Filters will probably do the trick and if you can see in the tank check for trash 1 Quote Robert"I reject your reality and substitute my own." Link to comment Share on other sites More sharing options...
cruiseliner82 Posted November 17, 2014 Share Posted November 17, 2014 Welcome aboard!! A couple things could also be an issue. The fuel return line could have a restriction. The fuel supply line could have crack and drawing some air, maybe a loose fitting. Also the supply line could have a weak spot and partially collapsing after a while. Good luck, Danny 1 Quote Link to comment Share on other sites More sharing options...
220cummins Posted November 17, 2014 Share Posted November 17, 2014 Multiple issues could be at hand. Start at the tank. Is it new and clean fuel? Is there rust that broke up during the trip in the bottom of the tank and causing a blockage at the pickup tube? Are the fuel filters new and tight? Are there any loose fittings on the pump or injection lines? Could be in the pump too just from sitting. 1 Quote Link to comment Share on other sites More sharing options...
farmer52 Posted November 17, 2014 Share Posted November 17, 2014 Agree with others. Easy check is to replace the fuel filters. If that doesn't do the trick, start at the tank and check everything to the pump including the return line. Also check the transfer/supply pump. Hope the filters to the trick.Is the fuel clear? If not, I would drain it and replace with fresh fuel.BTW, nice B.P.S. I am sure someone on here will have a few comments about the 2-stroker. 1 Quote Ken PRR Country and Charter member of the "Mack Pack" Link to comment Share on other sites More sharing options...
2stacksuperdog Posted November 17, 2014 Share Posted November 17, 2014 Welcome Quote Matt Link to comment Share on other sites More sharing options...
b61mack Posted November 17, 2014 Share Posted November 17, 2014 You might check the vent on top of the tank or in the cap. Quote Link to comment Share on other sites More sharing options...
Jeff M Posted November 18, 2014 Share Posted November 18, 2014 Nice clean B you have there. The 6/71 is not typical in a B, and you may hear some muffled groaning on the forum, but it's a good engine. Simple, lighter weight, starts easily even when it's cold out. Not as much power, tends to be louder, and usually leaks oil. However, I never met a 13 speed I didn't like. There was a day when the 6/71 ruled the highways; Detroit built a ton of them. I think you have an interesting combination there. Good luck with it! PS I agree with the others about changing out the fuel filters. Quote Link to comment Share on other sites More sharing options...
fifth wheel Posted November 18, 2014 Share Posted November 18, 2014 Nice work moving the radiator forward and lengthening the hood.FW Quote Link to comment Share on other sites More sharing options...
clemson_tiger29678 Posted November 19, 2014 Author Share Posted November 19, 2014 Thanks a ton guys! I'm super excited about my first big rig! I'm a classic car guy, and even more of a Corvette guy, so this is a little of course for me, but always wanted a semi...and I'm REALLY excited to find that the total height on mine is a hair less than 8 feet, which means it's going to fit under my house, in my shop!!! I'm going to grab some fuel filters and an oil and air filter and do some genearal maintence over the weekend to see if I can get the thing a little more road-friendly. Trying to decide which route to go with the truck...I've got ideas all over the place, from just leaving it like it is, to taking the fifth-wheel off and putting a period correct wooden flat-bed on it, to going all out custom and slamming it on air ride suspension. Seems like a fun vehicle that everyone looks at though! Quote Link to comment Share on other sites More sharing options...
HarryS Posted November 19, 2014 Share Posted November 19, 2014 Congrats on your purchase. Hopefully the problem is something simple that maintance will correct. Once you have it running and driving as it should you can enjoy while you decide. Quote Link to comment Share on other sites More sharing options...
Freightrain Posted November 19, 2014 Share Posted November 19, 2014 You can't really kill a Detriot............even though Yardo no one here would ever try Usually some basic maintenance will get it buz'n with full power again. Quote Larry 1959 B61 Liv'n Large...................... Charter member of the "MACK PACK" Link to comment Share on other sites More sharing options...
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