1wonton Posted October 23, 2022 Share Posted October 23, 2022 My 676 Thermodune surges at around 12-1400 rpms, about 45 mph. Changed fuel filters, new diesel but problem persists. If I add Seafoam how much should I use? ron Quote Link to comment https://www.bigmacktrucks.com/topic/70607-thermodyne-surging/ Share on other sites More sharing options...
terry Posted October 23, 2022 Share Posted October 23, 2022 more times than not, govenor needs rebuilt. terry 2 Quote Link to comment https://www.bigmacktrucks.com/topic/70607-thermodyne-surging/#findComment-513311 Share on other sites More sharing options...
BOBWhite Posted October 23, 2022 Share Posted October 23, 2022 There's a governor spring kit out there somewhere, although I don't know where to find it especially for the old American Bosh pumps. Quote Link to comment https://www.bigmacktrucks.com/topic/70607-thermodyne-surging/#findComment-513315 Share on other sites More sharing options...
theakerstwo Posted October 23, 2022 Share Posted October 23, 2022 Also the rear brg was a problem years ago.I dont know or cant remember but i think it could be removed with governor still on pump. Quote glenn akers Link to comment https://www.bigmacktrucks.com/topic/70607-thermodyne-surging/#findComment-513322 Share on other sites More sharing options...
Joey Mack Posted October 23, 2022 Share Posted October 23, 2022 Stanadyne... instead of Seafoam.. Put some in the fuel filters and the rest in the tank.. the mix is on the bottle... jojo Quote Link to comment https://www.bigmacktrucks.com/topic/70607-thermodyne-surging/#findComment-513325 Share on other sites More sharing options...
doubleclutchinweasel Posted October 24, 2022 Share Posted October 24, 2022 I'm a big fan of Opti-Lube. Adds lots of lubricity to the fuel, as well as the cleaning action. 1 Quote "Eagles may soar, but weasels don't get sucked into jet engines." Link to comment https://www.bigmacktrucks.com/topic/70607-thermodyne-surging/#findComment-513404 Share on other sites More sharing options...
1wonton Posted October 24, 2022 Author Share Posted October 24, 2022 OK; suggestions as to who can rebuild the fuel pump. Quote Link to comment https://www.bigmacktrucks.com/topic/70607-thermodyne-surging/#findComment-513405 Share on other sites More sharing options...
Joey Mack Posted October 24, 2022 Share Posted October 24, 2022 Good deal D.C.W. Can I get Opti-lube at NAPA? I have a diesel fork lift that could you a little love. It Has been my best employee for the last 12 years... Its full mechanical... jojo Quote Link to comment https://www.bigmacktrucks.com/topic/70607-thermodyne-surging/#findComment-513409 Share on other sites More sharing options...
doubleclutchinweasel Posted October 25, 2022 Share Posted October 25, 2022 I order it from Opti-Lube on Amazon 1 Quote "Eagles may soar, but weasels don't get sucked into jet engines." Link to comment https://www.bigmacktrucks.com/topic/70607-thermodyne-surging/#findComment-513440 Share on other sites More sharing options...
h67st Posted October 30, 2022 Share Posted October 30, 2022 On 10/24/2022 at 3:28 PM, 1wonton said: OK; suggestions as to who can rebuild the fuel pump. It's too bad you're in CA, we have a couple of shops in Ohio that still rebuild those pumps. Quote Link to comment https://www.bigmacktrucks.com/topic/70607-thermodyne-surging/#findComment-514042 Share on other sites More sharing options...
Freightrain Posted October 31, 2022 Share Posted October 31, 2022 On 10/30/2022 at 7:57 AM, h67st said: It's too bad you're in CA, we have a couple of shops in Ohio that still rebuild those pumps. I checked with local shop about going through my 237 pump and readjust the settings. They quoted $3500! Yikes, I left it alone. Quote Larry 1959 B61 Liv'n Large...................... Charter member of the "MACK PACK" Link to comment https://www.bigmacktrucks.com/topic/70607-thermodyne-surging/#findComment-514153 Share on other sites More sharing options...
HarryS Posted October 31, 2022 Share Posted October 31, 2022 I just had my 673 pump gone through which included cleaning, replacing O rings and a cracked line fitting. They did it on the truck. The cost was $1300 which I didn't think was too bad. The shop is located in norther VA. I would have said "yikes" to $3500 too. Quote Link to comment https://www.bigmacktrucks.com/topic/70607-thermodyne-surging/#findComment-514155 Share on other sites More sharing options...
davehummell Posted October 31, 2022 Share Posted October 31, 2022 When I bought my new to me engine the governor didn't act right so I took a chance on an injection pump rebuilder in Williamsport Pa. the guy had it fixed that day and it was just a shim adjustment and it was around 100 or so dollars I would recommend the place, but I just can't remember the name. There is a shop in Dunmore and I took the pump from my early 673 to see if it could be repaired and Charlie said throw the pump in the junk no parts available it was as if he really didn't want to touch the pump. Quote Link to comment https://www.bigmacktrucks.com/topic/70607-thermodyne-surging/#findComment-514156 Share on other sites More sharing options...
Freightrain Posted October 31, 2022 Share Posted October 31, 2022 Ya, local shop made it sound like they didn't want to touch it. And priced it as such. Lucky it runs great and no need to mess with it. Quote Larry 1959 B61 Liv'n Large...................... Charter member of the "MACK PACK" Link to comment https://www.bigmacktrucks.com/topic/70607-thermodyne-surging/#findComment-514159 Share on other sites More sharing options...
BOBWhite Posted November 2, 2022 Share Posted November 2, 2022 Injector cleaners are great but they're more of a bandage on a broken arm than a fix. Injection spray quality is the biggest determinate to how an old diesel will run. Most older pencil style injector's have Bocsh part's in em which can be pretty easy to rebuilt yourself if you know what you're doing. Quote Link to comment https://www.bigmacktrucks.com/topic/70607-thermodyne-surging/#findComment-514267 Share on other sites More sharing options...
h67st Posted November 5, 2022 Share Posted November 5, 2022 I had my 673 pump rebuilt at Purrformance Diesel in Fredericktown, they charged $1,100 which included several new parts. They are very particular, seemed like they wanted to make sure it was right. Quote Link to comment https://www.bigmacktrucks.com/topic/70607-thermodyne-surging/#findComment-514389 Share on other sites More sharing options...
1wonton Posted November 6, 2022 Author Share Posted November 6, 2022 On 10/30/2022 at 4:57 AM, h67st said: It's too bad you're in CA, we have a couple of shops in Ohio that still rebuild those pumps. Thanks. Yes, it is too bad I live in Taxifornia. I'd get out if I could. It's not the country I grew up in. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/70607-thermodyne-surging/#findComment-514436 Share on other sites More sharing options...
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