• Welcome to RCTalk! 🚀

    Join the #1 RC community where hobbyists connect, share, and get expert advice on RC cars, trucks, boats, drones, and more!

    • ✓ Friendly & passionate RC enthusiasts
    • ✓ RC tips & troubleshooting
    • ✓ Buy, sell & trade RC gear
    • ✓ Share builds & upgrades

K5.9 nitro engine

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, and others.
jmarcet85

jmarcet85

RCTalk Basher
Messages
73
Reaction score
0
Points
0
RC Driving Style
  1. Bashing
:angry:Hey guys I installed a k 5.9 and I have sealed it. For some reason I can not get it to tune. I've tried just about everything I've never had such a hard time getting a engine to run right. I think I'm about to take it out and trash a new engine cause it appairs to be hopeless. Anybody have any suggestions I have a brand new rebuilt 454 that I don't want to use yet but this k5.9 doesn't seem to be worth the hassle.
 
Ok! you sealed the engine did you seal the carb? Did you do any pre-heating, was that K5.9 brand new?

I need some more info, where are you running? How old is your fuel?

FYI: there are lots of people that have had problems with those engines, and have ended up shelving them or selling the on ebay.
 
Last edited:
Its new and yes its completely sealed. My fuel is good I run byrons race 3000 in all my trucks. It just baffles me I've never had these tuning issues. Its either too rich or too lean just can't find its sweet spot. Guess ill try and reseal the needles. I used the losi green oring grease. maybe I should get the ae green slim. never had an issue using this stuff tho.
 
5.9 update finally got her running good seems the low speed is way to rich at flush had to lean it more than I ever thought I would have to. Runs at about 240 which I'm happy with. Engine has quite a bit of torque feelin much better about this motor now but will be my first and last 5.9.
 
jmarcet85 said:
5.9 update finally got her running good seems the low speed is way to rich at flush had to lean it more than I ever thought I would have to. Runs at about 240 which I'm happy with. Engine has quite a bit of torque feelin much better about this motor now but will be my first and last 5.9.
Click to expand...

Why your last? It is running good, has "quite a bit of torque", and you seem to have a perfect temp with great response. Can you elaborate upon why this is a bad engine? I am asking because I have considered the 5.9. I know you had issues, but you learned through it and were successful at getting it to run well. Is there some other reason that you are not happy with it?
 
Its running ok but i can't get rid of the hang up after wot like its lean but it does it no matter what. Its very aggravating just in comparison to other big block i find its got good power but its unreliable my k4.6 losi 454 and even my jatos 3.3 a run great never any problems and if there was it was an easy fix but the 5.9 has just been a nightmare and id say maybe i just got a lemon but i havent read to many good reviews on it either.
 
Hey man, I see you're rocking a Losi Ten-T (your profile). How are you liking that? I've got an 810 that is an absolute phreak. That 3.4 is something else, eh? I am a newbie but pretty intimate with that Ten-series. I love it. If you've got any problems let me know.
 
Last edited:
yea I can't wait for the warmer weather Its brand new I haven't even broken it in yet but it looks like a awesome truck can't wait to drive it
 
jmarcet85 said:
Its running ok but i can't get rid of the hang up after wot like its lean but it does it no matter what. Its very aggravating just in comparison to other big block i find its got good power but its unreliable my k4.6 losi 454 and even my jatos 3.3 a run great never any problems and if there was it was an easy fix but the 5.9 has just been a nightmare and id say maybe i just got a lemon but i havent read to many good reviews on it either.
Click to expand...
I don't mean to be a bother, but please give me more details. You say it runs good but it is running lean during WOT? What makes you think it is running lean and is it only during WOT? Again, I just want a good understanding because I figured the 5.9 was solid. I mean, if we were talking about how the truck performs with the engine then it could be all kinds of issues causing that, but if we are talking about the engine alone, it would surprise me that the engine isn't solid. Maybe I am naive, but my understanding of these engines from the big names in RC, it is hard to really hate 'em. Unless you really torment and abuse them, they should be really solid- especially after 5-10 tanks. I guess a better way of putting it, any new engine, unless it has a manufacturers defect, should be superman after a few tanks. If not, there is another issue and it is usually user (not to say you don't know what you are doing, but perhaps it needs a different approach than you are accustomed to)?

Please do not take anything I am saying as a slight to you. I really am just trying to understand how the engine is flawed. Any details will really help because I have been seeking the 5.9 as a future purchase.
 
After you slow down from a wot dose the idle go up high for a sec or two then down to a normal idle?
 
Yes like i said earlier it hangs up and doesn't come down until the low speed needle takes over which is usally a sign of a lean tune even though its not if you do some more research on it youll notice that many people have issues with it. Alot of people sell them brand new and replace them rather then take a chance with it. In my opinion its a crap engine compared to other comparable engines. And just because hpi chooses to put there name on it doesn't mean its a solid engine. Thats just my thought on it. I also pulled the 5.9 the other day and put my rebuilt 454 back in and not a single problem runs like a champ.
 
your idle is to far open and your LSN is to rich and your HSN is to lean it is called a four cycle idle.
 
I've had x3 5.9 and never had a problem got over 10 gals on each one .
They are just a little tricky to tune that's all.
good luck
 
No its not four cycling i do know how to tune a engine also
 
what do you do when u can't figure something out hmnn you ask but I'm telling u thats not whats happening
 
If you feel like that about the 5.9 I'm one that's had far more problems with mine over the years. I first got it and right out of the box one of the carb needles was missing an O ring. It would not stay under 275 and I could not break it in. So here's a 600.00 truck with a defective engine that I now have to send back, I was not happy. It took HPI 3 weeks to get me the engine back and my season was over. Then I would get the machine gun sound you're describing for the longest time. Then I went pull start because the fuel at the time(traxxas 20% and Byrons 20% rtr) would make the one way bearing slip and would not start with the roto start. Then one day I decided to change things up a little: I ditched the R5 cold plug from HPI and put in a MC59 plug in there and it's like night and day. I also sealed the engine due to reports of machine gunning. Now she runs around 250 with the body on all day. I would say this engine is not for the inexperienced or the less patient. This motor will drive you crazy but when she's running good she's running good and is pretty good for a rtr engine. I also used the Associated green slime as a sealer along with blue rtv automotive sealant.
 
jmarcet85 said:
yea I can't wait for the warmer weather Its [Ten-T] brand new I haven't even broken it in yet but it looks like a awesome truck can't wait to drive it
Click to expand...

Oh yeah, you're in for a treat. Those 3.4's seem to get better with each gallon. I would not recommend cracking it open and sealing it - unless it needs it. I have three of them and have not had to seal any of them The vehicle itself is durable as hell. The only performance upgrades I'd recommend right off the bat is a 3-shoe clutch. I have both the M2C and TLR....recommend the latter as it has more tuning options, and swap out the diff grease with oil. Although it's discontinued, if you ever need parts you can leverage the SCTE library as the series of vehicles share >95% of the parts.

Attached are the part difference between Ten-T and the 810...the SCTE only has about five unique parts (most notably the chassis). The only weak area I've found are the engine mounts (they wear quickly). Other than that, it's a finesse vehicle that can take a beating...I run a very stiff setup with my 810 as I've found it performs best as a glider.

Finally - I empathize with what you are saying about your 5.9. I've had issues before with engines where everyone thought it was the tune but turned out to be something else.
 

Attachments

I do not have much experience with the K5.9 I own one and a buddy has run one. We both have has some carb problems but nothing major. I do know you must seal them up very well. Any carb that has the mid needle adjustment has always seemed to me to be finicky. After installing the Cen pipe on mine I can tell you that tuning was way easier and the power was way smoother. I seem to spend more time tuning the 5.9 compared to any other of my BB engines.
 

RC Builds

Back
Top