B&G V TWIN riding mower, LOW power

[beljohns]

All,

I picked up a 2006 (I believe) Cub Cadet RTZ 50" riding mower with B&S VTWIN 22 HP. It was used and cheap, and I thought I had enough know-how to get it going. Well, quite a few months later I'm still having a problem. Originally the left side pump was giving nothing, barely even could get moving the handle to move the tire. I pulled it off to find a cracked housing. After watching ebay a while, I found a new replacement (cross checked model several times) and got it put on. I went ahead and replaced the engine to pump belt. It was leaking oil pretty good, so but a new head gasket kit on it, new plugs, new fuel filter, reset the govenor, changed the oil. The engine starts easily, sounds good. I checked compressesion, 120 PSI and 110 PSI. I adjusted the handle on the new pump side to be about the same as the other side. However, after all that... I still have extremely low power. I'll define low power as it won't go that fast, and as soon as hit grass (mower deck off)... I can barely go. The right side (old pump) seems to have a bit more power than the left. I've tried all of the listed above, resetting valves a few times (.006" is thinnest feeler I have), adjusted throttle/carb, etc... I'm a bit at a loss. I'm not sure what the compression should actually be, but thought the 110-120 range would be ok. I would appreciate very much any assistance in logical troubleshooting. I am not a mechanic, but can turn a wrench. I'm trying learn about 2/4 stroke engines and such, thought this would be a good project...but now getting grumpy with it.

Thanks,
Ben

 

[mechanic mark]

Check air filter, engine has to breathe.

Post all numbers from engine data plate, everything, thanks. Bleed air from hydraulic system.

769-01636 Shop Manual

 

[beljohns]

Yep, put on a new air filter and pre filter. I did not try running it with no air filter, but could give that a try just to see if any difference. Can anyone confirm if the 120 and 110 compression readings sound like they are reasonable? Thanks.

 

[logan01]

Briggs is really cs on providing compression figures. Generally they'll state anything over 100 is acceptable. Over 100 and you minimally want each side within 10% of the other. Did you do a leak down test or a "standard" test? Regarding the valves, what are the factory specs for your model, both intake and exhaust? When sitting still and throttle wide open, does it sound/feel as though it really is full throttle or weaker than it should be?

 

[beljohns]

Thanks for the link to the manual. No, I have not bled air from hydraulic system... I'm not sure how to do that, is it specified in the manual?

I'm not sure exactly what #s from engine plate you're referring to, on the engine plastic cover I do see: 4075770317E1 and 040802YG39799.

When I checked the compression, I screwed the gauge and with other plug also out and throttle turned up, turned over the engine 4-5 times watching the gauge each time so see if the increments were about the same (Which they seemed to be) and then the top out pressure of 120 and 110. I don't know the difference between standard and leak down. I'm happy to do both, will need to research the procedures.

Valve clearance for both I believe are .006, at least that's what my research came up with.

As far as sitting idle with throttle wide open, it seems to sound like it could be "loud enough"...but I would say it does "feel" weak, hard to explain. The sound also seems less aggressive than it should, I say this by comparison to a similiar Troybilt zero turn of similiar engine size which what we are mowing the grass with right now.

I very much appreciate the responses so far, and do please keep them coming. I have learned a lot in working with this mower, and although really want to get it working... also want to learn along the way. Thanks.
-Ben

 

[logan01]

In all likelihood your compression is probably ok and doesn't sound related to the issue. Good chance the new tranny needs purging and is probably covered in the manual. When air is trapped inside the tranny, fluid cannot flow properly to drive the tranny. I have included a short video of the procedure. If the plugs for the tranny are too difficult to access or just a pain, and you have an external reservoir, just remove the cap and follow the video. If air is purged it will likely need more fluid. Adding more fluid through an external reservoir will go much more slowly than adding it through a fill plug. Ad fluid to the "cold" line.

https://www.youtube.com/watch?v=dJFgt0GgjNg

 

[beljohns]

Thanks, you bring up a good point. I forgot to add that detail. When I ordered the new transaxel, the unit I received was prefilled. I could find nothing in the 2 pages of instructions that came with it about purging. I attempted to perform the process in the video, but I'm not 100% sure I opened the bypass rod for the first go around. Anyway, after performing the process I checked oil level and it was about 1.5" below the top of the transaxel check fluid hole highest point (same as prior to performing the procedure). This seemed to be within the specs I have read about. After running it around and doing all the other stuff I've written about, I checked again the other night and still at the same level.

I will try to repeat the process again, this time opening the bypass the first time. Question though, if it turns out I need to add oil...what type should I use? I do not know what came pre-filled from Hydrogear, and I would think it would need to match.

Thanks,
Ben

 

[logan01]

probably 20-50 wt synthetic. Do you know the tranny make? There should be a sticker on it with a serial / model number. Probably Hydro - Gear trannys. Do they have external filters? If it's Hydro - Gear, here's their manuals. Hydro-Gear Service Repair Manuals

 

[beljohns]

Yep, hydrogear with no external filter.

 

[logan01]

Were you able to ID the tranny and locate the related manual? The manual should specify the type of oil.