1992 VMAX4 fuel pumps (wanted)

I need I need some new fuel pumps as it sounds like my engine is starving of fuel and it wont rev above 5K rpm and dies( I have rebuild the carbs and cleaned out the fuel tank), it idles fine and starts first pull so I am not completely sure if I need fuel pumps but I want to see what's out there

There are probably new pumps available, but I haven't seen any for awhile.

Shark

Any other sleds I could tear one off of of similar year?

Okay, so apparently the new fuel pumps are still available, but pricey. Especially when you have to have two. The OEM part number is
89A-24410-01-00. It looks like it was later replaced with 89A-24410-00-00. I found this on advancedengineparts.com
I know nothing about their website, but their prices were about half of what the other pumps I saw.

Replacement Fuel Pump compatible with Yamaha Part# 14-22291OEM# 89A-24410-01.

1997 - Mountain Max 800
1997 - VMax-4 800
1996 - VMax 500
1996 - VMax 600
1996 - VMax-4 800
1995 - VMax 500
1995 - VMax 600
1995 - VMax-4 800

Found a more detailed list for an SPI fuel pump on Amazon which is currently unavailable:

Compatible with Yamaha models below:
1992 VMAX-4 750
1993 VMAX-4 750
1994 VMAX 500
1994 VMAX 500 DX
1994 VMAX 500 LE
1994 VMAX 500 ST
1994 VMAX 600
1994 VMAX 600 DX
1994 VMAX 600 LE
1994 VMAX 600 ST
1994 VMAX-4 750
1994 VMAX-4 750 ST
1995 VMAX 500
1995 VMAX 500 DX
1995 VMAX 500 LE
1995 VMAX 600
1995 VMAX 600 DX
1995 VMAX 600 LE
1995 VMAX 600 ST
1995 VMAX-4 800
1995 VMAX-4 800 ST
1996 VMAX 500
1996 VMAX 500 DX
1996 VMAX 500 LE
1996 VMAX 500 XT Proaction Plus
1996 VMAX 600
1996 VMAX 600 DX
1996 VMAX 600 LE
1996 VMAX 600 Mountain Max
1996 VMAX 600 XT Proaction Plus
1996 VMAX-4 800
1996 VMAX-4 800 Mountain Max
1997 Mountain Max 800
1997 VMAX-4 800

Do you have a service manual for your '92? It can be downloaded from the first page of the General Questions Forum on this site. Also, '92 was the first model year and there are technical bulletins specific to your model. They can be found in our tech section.

Shark

Those are way more modestly priced, Thank you very much! I downloaded the manual and it appears very useful and it has even given me some ideas to testing my fuel pumps before I outright replace them. What am I looking for specifically as far as "technical bullet points". The sled has been sitting for a long time at least 10 years, I took the carbs out and cleaned them and then I put them back in after cleaning the tank and such, put it in and it was backfiring and runs better with the choke on, it wont rev above 5K rpm for longer than about 15 seconds. Also something to not this has been driving it around the yard and tonight I am going to put it up on a stand and see if I can get it to rev out and clean off some of the corrosion off the clutch surfaces, and see if it revs above 5K rpm, one other thing to consider is I have not been having the air boxes on while testing and the "filter" material has basically dissolved, so I do not know how much of a difference that would make. I think from the manual I am going to replace all my lines and see about putting a vacuum source on the hose that comes off the pump that would normally be going into the engine I believe for vacuum. I have bought some hard to get running well sleds before but it feels like I am doing double the work for one sled with the extra fuel pumps and so forth. I have been priming the system with using a garden hose cut with a rag and glove and blowing into the tank and it seems to be doing well as it idles well and starts first pull cold, but after riding it around and feeling it bog then I stop and it does and takes more than a few pulls to get it started again so this is what has led me to believe its the fuel pumps. Any more ideas of things I could try? Thank you again for your help, its nice to see these old forums still have active members that are very friendly and willing to help.

Thank you again for your help, its nice to see these old forums still have active members that are very friendly and willing to help.

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Thanks. I've been here over 20 years. Just an old guy watching over an old forum.

There are so many things that could be causing your problem. My sled sat for years while I was busy with other things. After I retired, I had time to try to get it running again. I could only get it to stay running with the choke half on. Dragged it in the barn and cleaned the carbs. There is a nice step-by-step with pictures in the tech section. I changed the fuel lines from the fuel pumps to the carbs because they were all brittle. That can cause cracks in the lines and suck air. Vmax-4's have a special fuel filter in the tank. It's a single filter with 2 nipples for the 2 fuel lines that come out of the top of the tank, and they're very hard to find. I drained the tank, installed my last one, mixed some premium gas with 100 octane race fuel, and started it up. It was still acting like it was starving for fuel, so I took it all back apart and took the floats out of the carbs. I cleaned the needle valve filter. That was not in the tech write-up. There was some crud floating around where the fuel comes in to the carbs. It ran very well after that. I always mix some Yamalube with the gas at the beginning of the season until I see the oil level in the oil tank going down.
It is recommended to run your sled with the air boxes on. Once you get it running like it should, you might want to put them back on. While you've got them off, take them apart and look at the white nylon collars where the rubber carb boots attach. They're called pipes and are part #19 on the Air Cleaner page in the service manual. They have white tabs that can get brittle and break off and get sucked into the engine and cause catastrophic damage. If any are missing, or pieces broken off, check your reed valves to see if there are any pieces stuck in them and get them out! Use the search feature at the top of this or any page on the forum and search "white tabs". It is a common problem that has ruined many engines. https://vmax4.com/threads/white-tabs-watch-out.11604/
As far as the filter foam material, check this out: https://vmax4.com/threads/possible-fuel-filter-issues.33244/#post-114887
This might be a longshot, but if your sled has been sitting a long time, you could have mice or a mouse nest in the exhaust. They like to drag insulation, string, corn, etc. into that hole they see coming out of the bottom of the hood and make new homes. That could restrict the airflow coming out.

The Search feature at the top right of any page on the forum is a good tool. There is a lot of information here, and any problem you may run across has more than likely been discussed before. I don't think you will find more information anywhere else on the web.

That should keep you busy for a little while. Post back here and let us know what you find.

Shark

So I installed the air boxes and it seemed to have "fixed" the problem at least from what little riding I have done around the yard. One of my white collars was broken and caught up in one of the plates of the carb when I took it apart the first time and I could no see anything that had gotten past that as I am pretty sure I broke it while pulling it off, as far as the filter mesh I ended up just using some scotch brite pads and cut them to the size of the hole and it seems to be breathing just fine through them. The fuel pumps didn't seem to lack pressure and so that is why I decided that maybe it just needs some restriction on the positive side of the carbs and maybe my problem is under fueling or even if the air/fuel ration was being thrown off without the air boxes. As far as more of the pieces of plastic reeds going into the engine just because I found one makes me worried so I may be taking this apart once more.

I'm happy it's running better now! I did a quick search and can't find the post, but I think the reason the airboxes are recommended was to put some restriction on the air going into the carburetors like you said. If I find that discussion I will put a link here. Keep an eye on the scotch brite pads so that they don't get sucked into the air box. Later Vmax-4's had a screen instead of the foam air filter. You may need to put a coarse screen under the scotch brite. It sounds like your plastic tabs are brittle. A lot of guys, including myself, just cut all of the tabs out to avoid later problems.

It sounds like you know your way around sleds. For a 30 year old machine that's been sitting more than 10 years, I'd say you've done a good job getting it back to where it is in running condition that you could go out and have some fun on it. They are reliable sleds, you just can't pass too many gas stations. I've got over 13,000 miles on mine and haven't ridden too much the last 6-7 years. It never left me stranded, even the night the driveshaft got ripped out of the bulkhead out racing on the lake. I know some other guys who have way more miles on theirs than I have on mine.

This might be the airbox thread I was thinking of: https://vmax4.com/threads/performance-air-filter.631/

Shark

I totally forgot to get back on here and thank you for helping me out with my sled, it has been a blast up in the mountains as it has a longer track kit on it, I know that it is a little off kilter to try and turn a vmax 4 into a mountain sled but it does pretty good. still have the original suspension assembly for it that the guy before me held onto so that was pretty sweet. Again thank you for your help and my apologies for the delayed response I do really appreciate it. Still working out some of the kinks in it but that's the fun of an old sled and I always seem to have something to work on so it keeps me busy.

I know that it is a little off kilter to try and turn a vmax 4 into a mountain sled

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No, not really. Others have done it and you can't deny that you've got plenty of power to ride in the mountains.

It sounds like you've been having fun with it. It's a lot more fun to ride them than to work on them! Here in Southern Michigan all of the snow is gone, and we didn't have much to start with. Everyone is talking like Winter is over. I'm glad you're getting some seat time.

Shark

Hopefully I can go out at least a few more weekends, snow is still at least 5 to 6 feet up around 10 thousand feet so its just a matter of getting up to that point but close to the parking lot is starting to get bare, one last storm this weekend here in Utah it looks like and then the wait is on until next winter. I was noticing the top end of the powerband was very weak, could not get above 55-60 on top of the mountain so I am thinking about taking those scotchbrite pads out as they may now be causing too much restriction on the air box, but also thinking it may be my fuel filter as I just put the old one back in until I could find a viable replacement but again it didn't look all that dirty to me but the take off from a dead stop is phenomenal and then as I ride it seems to be running out of juice and then I let it sit and idle for about 20 seconds and take off hard and then same thing so I assume its the fuel filter if not then the kind of air filter and then if not that then right back to fuel pumps so fingers crossed.