wrightgj

Hi,

I have been reading your posts and a lot of the problems you describe, I also had with my 4.6. I also got mine second hand, so suspected the engine at first.

My MGT had the problem of running fine (once started) until it would cut out (usually after a roll/long idle period). After it cut out I had to wait a few minutes for it to cool down before it would restart. I managed to get it going most of the time, by opening the carb a bit extra as I was pulling on the pullstart.

The idle on the truck was also 'lumpy' and it wouldn't idle long before cutting out. (ie you needed to keep blipping the throttle to keep the engine alive). I had the truck tuned great and the performance (once moving) was good.

The thing that cured all these problems (lumpy idle, cutting out etc) was fitting a new exhaust manifold and muffler. I put the LST set on the truck and hey presto, the truck runs like a dream. the idle is rock solid and will sit there for a whole tank if need be.

I ran the truck for the first time with the new exhaust system and only needed the glowstart to fire it up once (in the beginning!) in a 1 hour session.

So... try checking your pipe/manifold for leaks. It probably isn't the engine if you've already sealed it.

Another thing with your engine.. you will always get a 'pinch' when turning it over where it is hard to crank, this is normal and is how the engine generates it's power.

Here's a pic of the new setup:



cheers

jermainezey

i like that set u i will have to post sum of mine mgt 3.0 with the .21

teluan

Wow wrightgj! That is one of the best posts I have read thus far on this site. I have been reading about engine tuning for weeks and have not once read anything about the importance of the exhaust components. My MGT 4.6 has the exact same running characteristics as yours does prior to the exhaust swap including great performance when running (no lack of power or speed that is for sure). I had a feeling something more was going on than just a bad engine. I may have had the same issues with my new engine!!!

What pipe did you buy BTW?

Thanks so much!

jermainezey

her sum pic of my mgt 3.0 with a .21 in it i still have to put the pull starter and the muffler on it

jermainezey

here what it look like with the pull starter

wrightgj

No problem.
I just thought I'd share my experience with you as in my case it was the exhaust leaking, not the engine. Yours may or may not be the same lol.

Rather than rush out and get a new exhaust system, check yours for leaks. I bashed the truck (with the new header and pipe) again this week and the truck was crapped out again. The first thing I checked was the header seal (the one that is attached to the engine) and lo and behold it had a whopping big hole in it. You will need to unclip the spring around the engine case to check the seal, as it will usually split underneath where you can't see it. I'd check all the seals before investing serious cash.

I have the losi lst (2?) header and tuned HT pipe on it in that pic. I am using the stock motor, but to get the header to fit you need to grind the underneath of the connector on the header as the pullstart assembly is really bulky on those engines. I think i need to grind a bit more as it is fouling the rubber gasket and causing it to rip.

I am planning to fit the standard AE side header and an XTM pipe until I can replace the engine for one which gives more clearance between the exhaust port and the pullstart (I've hopefully got an STS 30 coming soon). Once that engine arrives, I'll put the losi exhaust back on.

cheers
KJ

jermainezey

do u have in pics of your truck

wrightgj

who me?

There is a pic of how it was in post 26... I'll post a new one with the AE header when I've re-installed the engine and cleaned it up this weekend.

cheers

almaidah

i have the same problem i thought it was the gas tank because i never could empty my tank and it cuts out at the same level and takes awhile to get it started again. i just bought mine new and only ran it 3 days now. i just drive on the street so you think i go an air leak too? i do see on my trany really small wet spots and i was wondering if something was wrong being a new truck

jermainezey

sound ike u my have a hole in your fuel line

theRCreverend

I've worn out many motors over the years. They run like this when the compression is starting to get too low.

jermainezey

he right

almaidah

this is a brand new truck though no air leaks in the hose i checked

jermainezey

are u too lean

almaidah

no all the settings are good and i never messed with the mid needle

jermainezey

what kind of engine do you have and what size is it and how much fuel have u ran thur it

theRCreverend

How have you checked for vacuum leaks? Take the engine out and seal everything with engine sealant.

jermainezey

makes sure your carb is on right and on there good

almaidah

ok i dont know what happened but i works now i can go through a full tank now

jermainezey

what do u do to get it to work

almaidah

well i blew water through the hoses to check for leaks and found none, then i was messing with the carb and i adjusted the carb the part with the rubber on it that flexes i turned that around some and ran a full tank through and it been working right now so i put about 4 tanks on it and no problems so i think the plastic part might not of been on to good.. i had so many problems with this truck from day one. and it was brand new.. my first problem when i was breaking in the truck was the screw that holds the front shaft on came lose during breakin and it caused the breaks to lock up because it tore the plastic from the brake area then the steering servo went out the same time. ae sent me new parts though..

driller2948

Do you still have the primer bulb installed on the fuel line? They have a tendency to leak. Take it off. Don't run any filters except the stock filter in the tank. Run only enough fuel line from your exahust to the tank same goes for the tank to the carb one or two small loops in the fuel line is ok.