Need to be schooled on turbos

[gdhillon]

Long story short, I bought a used silber turbo with redline controller and had it installed on my sled.

Pre-turbo (Engine got a full rebuild two or so rides before the turbo) the sled would start within two pulls all the time. Now it’s very temperamental when it comes to starting. If I am riding around and shut it off and restart almost right away it’ll flash up after a pull or two. And if it sits for long enough, sandwich break it’ll usually start within 1-2 as well. However, it doesn’t consistently start well.

Could it be an issue of my fuel pump going bad? I am thinking it’s not the filter cause it runs well once it’s started

I was running 50:50 94 and av, going forward I’ll just be runnin straight av

As far as numbers go I was 10#, 11.2 afr and 8300 last ride, however my prim spring was broken

thanks in advance

Edit: my mechanic had installed a regulator in the fuel return after the fuel pressure guage.(this was when he did the turbo) When it was really hard to start I’d have to pinch the line under the fuel pressure guage and it would usually fire after three-four quick pulls. When I say quick I mean let the cord go in 3/4 of the way then pull again sort of deal.

I have now removed that regulator and installed a barbed fitting to join the lines back up, it’ll start now without pinching that line, however it still takes a few pulls usually

 

[TROLLCAT]

spark plugs try some new ones

 

[snochuk]

Try 91 in your 50 50 mix.
Get rid of the ethanol completely from your mix.

 

[kingcat162]

What breed of sled? I'm familiar with the redline box if you need help with it - I had a hard start issue on my xm Doo - turned out to be stock reed cages were bent

 

[Dragonalain]

Seen in your signature your rockin a pro rmk. Usually your fuel pump will work or it won’t. Put a clamp meter on it. If it’s under 5 amp it’s good. Usually a hard start on those sleds is caused from low compression or bad reeds. This past winter my tpro on my last trip the sled was getting hard to start. I knew it was going to go down soon. 3 days later it popped. There was a pretty nasty crack in cyl on the side that melted. I’m not sure if that caused the problem or it it crack after the damaged occurred. Dropped a cyl at the Bullpen in revy. Drove it back to full speed on one cyl as my buddies still wanted to sled some more.
Last time I rebuilt this thing was 2015. I got redline electronics in 2016, very pleased always runs good. I bet this 2011 Polaris 800 engine has around 100 days on it. The last two years I’ve been occasionally running 15# on 116 race.

 

[2Turnipsinheat]

What breed of sled? I'm familiar with the redline box if you need help with it - I had a hard start issue on my xm Doo - turned out to be stock reed cages were bent

I had a similar problem on an xm and it turned out to be the rave valve check valve needed replacing

 

[Cableguy]

tps can be fussy also

 

[kingcat162]

I had a similar problem on an xm and it turned out to be the rave valve check valve needed replacing

The check valve made it hard to start? The check valve controls the raves - if your check valve manifold was buggered it should have just affected your midrange and top end performance - running the raves off of the throttle body is the fix for that unit

 

[gdhillon]

Try 91 in your 50 50 mix.
Get rid of the ethanol completely from your mix.

The 94 is E free stuff from chevron

Im curious, why would running a lower octane with av help?

 

[gdhillon]

What breed of sled? I'm familiar with the redline box if you need help with it - I had a hard start issue on my xm Doo - turned out to be stock reed cages were bent

It’s a 13 pro rmk 800

 

[gdhillon]

Seen in your signature your rockin a pro rmk. Usually your fuel pump will work or it won’t. Put a clamp meter on it. If it’s under 5 amp it’s good. Usually a hard start on those sleds is caused from low compression or bad reeds. This past winter my tpro on my last trip the sled was getting hard to start. I knew it was going to go down soon. 3 days later it popped. There was a pretty nasty crack in cyl on the side that melted. I’m not sure if that caused the problem or it it crack after the damaged occurred. Dropped a cyl at the Bullpen in revy. Drove it back to full speed on one cyl as my buddies still wanted to sled some more.
Last time I rebuilt this thing was 2015. I got redline electronics in 2016, very pleased always runs good. I bet this 2011 Polaris 800 engine has around 100 days on it. The last two years I’ve been occasionally running 15# on 116 race.


https://uploa.tapatalk-cdn.com/20200411/b56dfaf5ad8209015ba48b43a23dcba0.jpg

The engine was just rebuilt, within 50 k I’d say. Reeds were done at that time as well.
If it is in fact reeds causing the starting issue wouldn’t it be a hard start everytime?

 

[kingcat162]

It’s a 13 pro rmk 800

Check your compression -due to the ether bunny usage - who did the rebuild and install? - if it was not yourself - I'd be going over the whole thing top to bottom - I just did a 2015 shortblock swap over - and it started first pull

 

[gdhillon]

tps can be fussy also

I had tps issues a little while ago, had the stealership set it to .7 I believe it was

That being said sometimes it cold idles at 2k then will eventually drop to 1800-1600 ish

 

[gdhillon]

Check your compression -due to the ether bunny usage - who did the rebuild and install? - if it was not yourself - I'd be going over the whole thing top to bottom - I just did a 2015 shortblock swap over - and it started first pull

I had shawn at mcbride small engine do the rebuild as well as the turbo

 

[2Turnipsinheat]

The check valve made it hard to start? The check valve controls the raves - if your check valve manifold was buggered it should have just affected your midrange and top end performance - running the raves off of the throttle body is the fix for that unit

Yeah couldn't figure it out. Almost got stranded as it wouldn't start. Took it in and replaced the check valve never had the issue again. I see what your saying but not sure.

 

[gdhillon]

The check valve made it hard to start? The check valve controls the raves - if your check valve manifold was buggered it should have just affected your midrange and top end performance - running the raves off of the throttle body is the fix for that unit

I did just clean both my power valves, and replaced one bellow as it was torn, still no difference in starting, I didn’t replace the little springs on the bellows though

 

[gdhillon]

Yeah couldn't figure it out. Almost got stranded as it wouldn't start. Took it in and replaced the check valve never had the issue again. I see what your saying but not sure.

hmm perhaps this is my issue to then? Seems to run okay mid/wide open though

 

[kingcat162]

I did just clean both my power valves, and replaced one bellow as it was torn, still no difference in starting, I didn’t replace the little springs on the bellows though

I'm leaning more towards a fueling issue - if your having to ether bunny it this Easter - and she fires up after the bunny treatment - that means you got spark and it's not TPS - you got air you got spark and you got ether bunny fuel - and she runs - thinking fuel pump or something in the fuel system itself - shouldn't be fuel and octane and av gas etc - various of these fuels usually affect more of the bottom end throttle response not so much with the cold start usually - I'm speaking from experience from running various fuels myself - just not on a Polaris tho - when you do get it starting good tho - ditch the av gas and shoot me a PM and use a pop bottle with 40:1 mix fuel in it with a tiny hole in the lid for priming instead of the bunny fuel

 

[gdhillon]

I'm leaning more towards a fueling issue - if your having to ether bunny it this Easter - and she fires up after the bunny treatment - that means you got spark and it's not TPS - you got air you got spark and you got ether bunny fuel - and she runs - thinking fuel pump or something in the fuel system itself - shouldn't be fuel and octane and av gas etc - various of these fuels usually affect more of the bottom end throttle response not so much with the cold start usually - I'm speaking from experience from running various fuels myself - just not on a Polaris tho - when you do get it starting good tho - ditch the av gas and shoot me a PM and use a pop bottle with 40:1 mix fuel in it with a tiny hole in the lid for priming instead of the bunny fuel

I’ve never used ether on this sled lol, i feel I misstyped something?

 

[snochuk]

The 94 is E free stuff from chevron

Im curious, why would running a lower octane with av help?

It's getting rid of the ethanol that can predetonate/knock .
If you are 94 e free then going to 91 e free would be a step backwards.