thehorse 221 #1 Posted February 6, 2015 Well the 416h has been helping move a lot of snow in little increments but nothing major. I have noticed that the engine definitely has an up and down cadence to it. It surges up and down. Nothing major but enough for me to make a post. I've checked to make sure the plug wires were on but not much else. It's just to cold to muck with in the non heated garage. Any suggestions? I could be imagining things but it may have a puff of smoke on the surge when warming up and choked, maybe 10 seconds worth. Any insight would be appreciated. Share this post Link to post Share on other sites
varosd 1,185 #2 Posted February 6, 2015 I think the most common issues is the Onan carbs getting dirty..I would pull the top off the carb, check the float and remove needle valves and clean all ports. I'm sure you run hi test/ethanol free gas. my 416-H did the same thing about 2 months ago and after carb cleaning she runs great. only other thing could be governor. Share this post Link to post Share on other sites
cheesegrader 433 #3 Posted February 6, 2015 Onan surge is usually a fuel delivery problem. A good carb cleaning works most of the time, but consider old fuel lines, weak fuel pump, and clogged fuel shut-off valve as well. Share this post Link to post Share on other sites
Ed Kennell 37,492 #4 Posted February 6, 2015 Since it's too cold to do the carb cleaning now, I would give her a good dose of Sea Foam for now and if the symptoms persist, follow Dons advice when it warms up. I cleaned the carb on my 520 3 times before the surging finally went away. Share this post Link to post Share on other sites
thehorse 221 #5 Posted February 6, 2015 Thanks, I was thinking the exact same things. I'm out of seafood so ill pick up some tomorrow. I'll let you know how things progress. Len Stay warm all! Share this post Link to post Share on other sites
Tankman 3,516 #6 Posted February 6, 2015 My '90 520-8 used to surge. Doesn't since I started adding Berrymans to the fuel. I use Berrymans, 1 oz per gallon and it does keep fuel line and carb clean. No more surging You can find Berrymans in most auto supply stores. Good stuff and inexpensive. Share this post Link to post Share on other sites
Wheel Horse Collector 47 #7 Posted February 6, 2015 I had one that surged I took the carb completely apart, blew it out, put It back together and I haven't had a problem since. So I would take the carb apart and give it a complete cleaning Share this post Link to post Share on other sites
Theroundhousernr 589 #8 Posted February 6, 2015 Thanks, I was thinking the exact same things. I'm out of seafood so ill pick up some tomorrow. I'll let you know how things progress. Len Stay warm all! All great suggestion. Just try to keep the seafood out of the onan. Especially shellfish, really tends to clog things up Sorry, cracked me up this morning. 3 Share this post Link to post Share on other sites
Ed Kennell 37,492 #9 Posted February 6, 2015 Enough Roundhouse.....clam up 2 Share this post Link to post Share on other sites
thehorse 221 #10 Posted February 6, 2015 Again with the spell check.....Should have noticed something fishy. Not sure if its a FLUKE or what but usually leaves me crabby when it does this. 6 Share this post Link to post Share on other sites
jackhammer 546 #11 Posted February 7, 2015 You guys are cracking me up Share this post Link to post Share on other sites
squonk 40,743 #13 Posted February 7, 2015 I don't think you can use a FLUKE to fix the carb! Use it on the gauges and lights! Share this post Link to post Share on other sites
nylyon-(Admin) 7,183 #14 Posted February 7, 2015 On my 416, there's a bowl plug which can be removed. When you remove that you have access to the main jet. You can then very quickly and easily spray carb cleaner directly into the jet and it'll clean that and the float bowl. It's a quick and easy job and doesn't require removing the carb or top of the carb. Takes a few minutes and it fixed the surging on mine. 1 Share this post Link to post Share on other sites
Ed Kennell 37,492 #15 Posted February 7, 2015 I hope you get her running better Horse. I'd hate to see you out there FLOUNDERING around in this new snow that's coming. Share this post Link to post Share on other sites
AMC RULES 37,102 #16 Posted February 7, 2015 On my 416, there's a bowl plug which can be removed. When you remove that you have access to the main jet. You can then very quickly and easily spray carb cleaner directly into the jet and it'll clean that and the float bowl. It's a quick and easy job and doesn't require removing the carb or top of the carb. Takes a few minutes and it fixed the surging on mine. Quick and easy... exactly where is this bowl plug located? 1 Share this post Link to post Share on other sites
nylyon-(Admin) 7,183 #17 Posted February 7, 2015 The 416 is snowed in at the moment, so I can't look. But if I remember correctly (and we all know about my memory ) its on the front of the carb as sitting on the seat. Or could be on the back? but it's definitely at the bottom of the bowl. 1 Share this post Link to post Share on other sites
thehorse 221 #18 Posted February 7, 2015 Do you have a pic of plug location? I like easy. I would PERCH myself up to look around and find it but a pic would be awesome. Thanks 2 Share this post Link to post Share on other sites
nylyon-(Admin) 7,183 #19 Posted February 7, 2015 Sorry, wish that I did. I know it's there, you need to remove the entire air cleaner housing, but it's there on my 1994 416. As mentioned in the prior post, I believe it's in the front as sitting on the seat. Share this post Link to post Share on other sites
AMC RULES 37,102 #20 Posted February 7, 2015 Do you have a pic of plug location? I like easy. I would PERCH myself up to look around and find it but a pic would be awesome. Thanks Ditto... but, my little arms are so weary. Share this post Link to post Share on other sites
1977.d-160 1 #21 Posted February 17, 2015 Throwing this out there as I've heard (not witnessed) it being a cause of similar symptoms: check the governor spring. Sometimes when they age there isn't enough tension and that can cause 'rev surging'. Hope that helps - good luck! <insert clever oceanic pun here> Share this post Link to post Share on other sites
thehorse 221 #22 Posted February 17, 2015 I will check the spring. Sounds plausible to me. Thanks. Share this post Link to post Share on other sites
Damien Walker 241 #23 Posted March 19, 2021 Late to the party as always.....but my 518H is sturgeon too! (couldn't miss that one). I've cleaned the carb but probably not the main jet...if it requires access via the bowl plug. I shall investigate over the weekend. Share this post Link to post Share on other sites
Bak106 8 #24 Posted March 19, 2021 Anyone know what size oil plug is on the kt17qs? Cannot find any info! Middle of oils change and cannot not find mine Share this post Link to post Share on other sites