walls

The truck is a savage x, the motor is a modified picco.28. On a full throttle run it has dead spots as it comes up in the rpm range. It sounds exactly like a very lean motor would sound, but it is not. It still does it whether I make it extra lean,extra fat,or perfect. Sometimes it will go away and continue running up till top rpm. I am lost with this and cant seem to find the problem or fix it. Any help would be appreciated. Thanks Walter

3-172IN MTN

Could it be the throttle linkage hanging up?

supertib

that can be a dirty carb ! what fuels,plug,pipe......?

walls

dynamite platinum 086 pipe, Odonnell 30% fuel. Ofna racing plug.

walls

Just noticed on the plug package it says for ofna/picco .21????? Could this be my problem????

supertib

it is very possible your carb is gummed up ..... it sounds like it is a fuel delivery issue......... who modded the engine ?

walls

You. About 2 years ago. Starts up great,idles great ,seems to be fast as hell once it gets past the dead spots, but they really annoy me. I like my stuff to run prefect.

supertib

well what you are describing sounds like an issue with fuel supply...has the engine sat for any time ? sometimes the carbs ca gum up with old fuel and cause all sorts of issues, same goes for the fuel tank and fuel lines....fuel can also spoil, and glowplugs can go bad..... plenty of little things can cause these little engines to run funky...... without seeing a video it is hard to know exactly what the engine is doing ......

walls

How would I go about cleaning the carb? Should I use regular carb cleaner? Thanks for your help. Walter

supertib

best bet is to give me a call and we can discuss what to do...... to clean a carb you need to complete take it appart...then clean all the pieces, blow the fuel passages out with air, then reassemble the carb

Krawlin

My stock Picco P3-28 did this through the midrange, not really a dead spot, just midrange lean out. I too was running a Dynamite 086 pipe and I have read alot of posts on other forums about the infamous Picco midrange lean out issues when used with top end pipes like the 086 (which are actually just as good on the bottom end as the top end). However, if I rolled into the throttle like I was driving an electric car is the only time it would ever do that. If I blipped the throttle/very quick trigger movements rather than smooth movements, it wouldn't do it. Try driving it a bit more aggressively and see if it helps at all, like I said mine would only do the midrange lean out crap if I drove it smooth like an electric car. Not sure if this is the same issue here but it sounds similar.

Spdfrk

Have you "sealed" the engine? Sounds like you might have an intake leak somewhere.

supertib

At the transition where the LSN exits the spray bar the engine can act funny if the throttle is held in that position...triggers are meant to be blipped, not bled.............. Wall's is this issue happening at part throttle or full throttle................

savagecommander

the mid needle adjustment would clean up the transition from low speed to high speed. i always use carbs with three needles for this reason alone.

walls

It happens at full throttle,but its when the motor is about half way through its rpm band. Bottom rpms are clean and top rpms are clean. I have not had time to clean the carb yet.

BudBud

While you are checking things out, take a really close look at the bellows that cover the end of the slide. The accordion looking plastic bellows. Sometimes a hole worn in them or a small crack will do what you describe, allowing air to bleed into the carburetor slide.

Nice to see the MTN man back from the paid vacation! Tib, you never call anymore.... what's up my man? 8)

bigwaltc

sounds like a air leak to me[sm=shades_smile.gif][sm=shades_smile.gif][sm=shades_smile.gif]

cholet

the problem might not be the engine. the same thing happened with mine, i needed a new throttle servo.