Hard Starting - could it be fuel pump? - Snowmobile Forum: Your #1 Snowmobile Forum

rgoers · 02-04-2013, 08:05 AM

I had an issue with my '04 RMK trail last season... just before I put it up for the summer; I was having a hard time starting it. Used to be a '2-pull wonder', but now it was taking several pulls to get it running. I figured it was low compression (measured 100) so I ordered pistons, rings, needle bearings, etc. and let it sit for the summer.

A couple weeks ago I finally rebuilt the top end. Everything went as planned... got it honed out and everything. Old pistons looked good (maybe running a little lean) but there was evidence of some blow-by, so I changed them anyway.

The problem is - I'm *STILL* having an issue getting it started! Cold takes several pulls, and if I shut it off warm, forget about starting it until after I've sufficiently pulled my arms off...

Once it's running, it seems to do fine and stays running. Got higher speeds out of it yesterday than before the rebuild…

So that’s got me to thinking: The problem started before rebuilding. Low compression before rebuild *may* have been from lack of lubrication (i.e. gas/oil in the cylinder). In other words – I couldn’t pull it over fast enough to get a good reading. If I remember correctly (when it was starting fine), the first pull used to be somewhat hard because of thickened oil in cylinders. Second used to be a LOT easier, and that’s when it used to start. Before putting it away, and after the rebuild, it has been pulling hard all the time (no oil/gas in cylinders?) Plugs are coming out mostly dry when I check them. My best guess at this point is there’s a problem with the fuel pump. Does that sound about right?

I’m heading to the “how to” section now to see what I need to do to test the pump…

rgoers · 02-04-2013, 09:28 AM

BTW - anybody know what model pump is in this sled? I can get the Polaris part number (3089751 ), but that doesn't help me. Is it a Mikuni? What Mikuni model number (i.e. DF-52 , etc.)? What would be the gallons/hour output of the stock pump?

I can look when I get home, but was hoping to get parts ordered before then...

**kccats** · 02-04-2013, 06:51 PM

First did you chamfor the ports? Did you clean the carbs? Does the fuel pump, pump much at all?

rgoers · 02-04-2013, 08:29 PM

All I did was break the glaze... Nikasil sleeves, so I didn't want to take off any material. The engine has over 7000 miles on it, so I didn't touch the ports.

I have cleaned the carbs - removed, flossed, etc. Like I said - it started getting hard to start at the end of last season.

I have not had a chance to test the fuel pump yet. I just ordered a Mikuni pump for it, since the Polaris rebuild kit costs the same as the new Mikuni. Can't seem to be able to find a rebuild kit for the stock Taiyo Giken, aside from getting it from Polaris. Might as well switch over to the Mikuni now - I can always get a rebuild kit for the Mikuni for a few bucks.

**kccats** · 02-05-2013, 06:57 AM

The reason to round the edges is to not snag a ring! Good call to upgrade!