Please see the attached PDF documents related to this engine. File names indicate the nature of the document.

The VMX-46PRO Engine was first produced in September of 2002 and released to the North and South American markets in November. Some engines may have been introduced in Australia beginning in October 2002.

The engine remains largely unchanged as of May 2004 with production changes limited primarily to the crankshaft, front bearing and drive washer system.

There have been three different crankshafts used in the VMX-46PRO since inception.

All three crankshafts have the same 1/4 x 28 NF thread and use the same prop nut and prop washer. The drive washer (behind the prop) is different in some cases and so is the front bearing. The following information helps to identify the crankshaft type and the drive washer and front bearing that matches each of the different types of crankshafts. The most easily identifiable feature of each crankshaft is shown below in italic type.

Type A Crankshaft - Part #VXR-462050A
-  Used in production until approximately Sept-Oct 2003.
- Has a 7mm outside diameter (OD) where it passes through the front bearing.
- Is silver  in color on the back face and the back face has notches that run through the entire back disc.

Type B Crankshaft - Part #VXR-462050B
- Used in production from Sept-Oct 2003 through approximately Nov-Dec 2003
- Has a 8mm outside diameter (OD) where it passes through the front bearing
- Is black in color on the back face and the back face has notches that run only partially through the back disc

Type C Crankshaft - Part #VXR-462050C
- Use in production beginning in Dec 2003
- Has a 8mm outside diameter (OD) where it passes through the front bearing
- Has two flat shoulders  just ahead of the front bearing to engage with the thrust washer
- Is black or silver in color on the back face and the back face has notches that run through the entire back disc

The differences in Crankshafts also are matched with some changes to the front bearing and drive washer.

Type A CrankShaft with OD 7mm - #VXR-462050A
- requires Type A Front Bearing with inside diameter (ID) 7mm - #VXR-462055A
- requires Type A Drive Washer (cone shape inside) - #VXR-462070A

Type B Crankshaft OD 8mm - #VXR-462050B
- requires Type B Front Bearing with ID 8mm - #VXR-462055B
- requires Type B Drive Washer (cone shape inside) - #VXR-462070B

Type C Crankshaft OD 8mm with shoulders - #VXR-462050C
- requires Type B Front Bearing with ID 8mm - #VXR-462055B
- requires Type C Drive Washer with flats to engage with shaft shoulders - VXR-462070C 

The VMX-52PRO Engine was first produced in September of 2003 and released to the North and South American markets in November 2003. Some engines may have been introduced in Australia beginning in October 2003.

The engine remains largely unchanged as of June 2004 with production changes limited primarily to the crankshaft, front bearing and drive washer system.

There have been three different crankshafts used in the VMX-52PRO since inception.

All three crankshafts have the same 1/4 x 28 NF thread and use the same prop nut and prop washer. The drive washer (behind the prop) is different in some cases and so is the front bearing. The following information helps to identify the crankshaft type and the drive washer and front bearing that matches each of the different types of crankshafts. The most easily identifiable feature of each crankshaft is shown below in italic type.

Type A Crankshaft - Part #VXR-462050A
 -  Used in first production lot until approximately Oct-Nov 2003.
- Has a 7mm outside diameter (OD) where it passes through the front bearing.
- Is silver  in color on the back face and the back face has notches that run through the entire back disc.

Type B Crankshaft - Part #VXR-462050B
- Used in production from Oct-Nov 2003 through approximately Feb-March 2004
- Has a 8mm outside diameter (OD) where it passes through the front bearing
- Is black in color on the back face and the back face has notches that run only partially through the back disc

Type C Crankshaft - Part #VXR-462050C
- Use in production beginning in March 2004
- Has a 8mm outside diameter (OD) where it passes through the front bearing
- Has two flat shoulders  just ahead of the front bearing to engage with the thrust washer
- Is black or silver in color on the back face and the back face has notches that run through the entire back disc

The differences in Crankshafts also are matched with some changes to the front bearing and drive washer.

Type A CrankShaft with OD 7mm - #VXR-462050A
- requires Type A Front Bearing with inside diameter (ID) 7mm - #VXR-462055A
- requires Type A Drive Washer (cone shape inside) - #VXR-462070A

Type B Crankshaft OD 8mm - #VXR-462050B
- requires Type B Front Bearing with ID 8mm - #VXR-462055B
- requires Type B Drive Washer (cone shape inside) - #VXR-462070B

Type C Crankshaft OD 8mm with shoulders - #VXR-462050C
- requires Type B Front Bearing with ID 8mm - #VXR-462055B
- requires Type C Drive Washer with flats to engage with shaft shoulders - VXR-462070C 

Question: When I try to change the throttle setting I find that the throttle barrel is very stiff or jammed in position. What is causing this and how do I resolve it?

Answer: This does not occur often but can occur when any sort of debris gets into the carb and lodges between the rotating barrel and the carb body or in the slot that is located in the rotating barrel into which the idle stop screw engages. It can also occur when debris scores the barrel or carb body or the edges of the idle stop screw slot.

It most cases it is resolveable while in some cases it requires parts replacement.

Procedure:

First of all make sure that the servo and control linkage between the servo and the carburetor are moving fully and freely.

Secondly make sure the prop is balanced and that you do not have a vibration problem. We have seen out of balance props cause extreme vibration that will cause the carburetor rotating barrel to oscillate rapidly and jam the barrel.

If these preliminary checks do not solve your problem you will need to inspect your carburetor more carefully as follows:

Please read these instructions from beginning to end twice before taking any action.

a) Consult the Owners Manual and Read Me First sheet which came with your engine. If you have misplaced these documents you can download a copy of the manual from the support section at www.richmondrc.com. See the VMAX section of our Knowledge Base.

b) Consult the exploded 3 Views in the Owners Manual (usually found on Page 6).

c) Loosen the cinch bolt nut (see 2090) and remove the carburetor.

d) Apply oil or after run oil to the carb rotating barrel.

e) Remove the idle stop screw (see 3080). Examine the end of the screw carefully. It should not have any burrs or nicks. If the end of the screw is irregular in shape or damaged in any way the screw will need to be replaced.

f) Carefully remove the carburetor rotating barrel complete with throttle arm. (see 3040). Watch for and retain the spring (see 3030). Take note of which way the spring is tapered and how it is positioned.

g) Carefully examine the rotating barrel and the carburetor body. Remove any debris. If the carb body or rotating barrel or the slot in the barrel for the idle stop screw are scored or have damage to their surfaces the carb and/or barrel will need to be replaced.

h) Flush the hole where the idle stop screw goes. Make sure no debris remains.

i) Reassemble the carburetor after applying Pacer After Run oil or other thin oil to the parts. Make sure the spring (3030) is inserted correctly.

j) Carefully screw in the idle stop screw.

k) Test for easy rotation via the throttle arm.

If after cleaning out any debris and carefully reassembling the carburetor, the problem persists, the carburetor or at least the parts noted above, will need to be replaced.

Question: What type and length glow plug should I use in my VMAX 46PRO or 52PRO?

Question: The Idle Stop screw (#VXR-463080 which is #3080 in the exploded 3 view in the Owners Manual) appears to have stripped threads at the non-head end of the screw. Is this normal?

Answer: Yes

Better Answer: The screw is threaded first and then turned down (made thinner) on the non-head end to engage smoothly in the slot in the throttle barrel. The turned down portion is narrower than the threaded portion. Some appearance of threads may remain after the screw has been turned down. This is normal and does not indicate stripped threads.

Question: I have inadvertently adjusted the low speed mixture to the point that I am not happy with where I ended up. I want to return to the original factory setting and then work from there but I forgot to take note of the original setting. Can you tell me the original factory setting for the low speed mixture screw on a VMAX 52PRO?

Answer: Yes. Here are some tips to help with this.

a) Please review carefully the owners manual that came with your engine. Look for the section related to adjusting the low speed mixture. As of  20020719 this was sections 6.9 and 6.10. Read these sections over carefully and them read them again. Do not proceed until you have read these sections AND have met the conditions stated therein. In particular note that you should not be mucking with the low speed mixture screw until you have broken in the engine to the degree specified in the owners manual. Mucking with the low speed mixture screw too early is a waste of time and will cause you a bunch of grief and aggravation for nothing.

b) After reading the sections of the owners manual related to adjusting the low speed mixture, if you want to return the low speed mixture adjustment screw to its original factory location, please do the following:

• Rotate the screw clockwise so that it moves into the carburetor while counting the rotations until the screw becomes tight to turn. Do NOT OVER TIGHTEN... once the screw is snug and does not want to turn, STOP. This is not a tractor and there are no points given for brawn here... stop turning when the screw starts to get snug.
• Now turn the screw counter-clockwise so that it starts to back out of the carburetor.
  • Rotate the screw and count four (4) full turns for a 46PRO, or
  • Rotate the screw and count three (3) full turns for a 52PRO

Thats it. You are more or less back to the original factory setting.

Question: The muffler bolts in my engine are hard to turn. I have been careful not to cross thread the bolts where they engage with the muffler. The threads on the bolts appear to be incompatible with the threads in the muffler. What is going on here?

Answer: There may be a bit of residual finishing residue in the muffler threads. The threads in the muffler holes and on the bolts are correct. Remove the residue and the bolts will work fine.

Better Answer: The muffler front section is a cast component. After the two muffler bolt holes are drilled and the threads tapped, the front section is sand blasted and treated during a finishing process. Some residue from the finishing process may be in the muffler bolt hole threads. To remove this residue simply quirt a bit of oil into the muffler holes and apply a bit of oil to one of the muffler bolts. Screw the bolt into the muffler hole about 1-2 turns and then back it out. Clean off the oil from the bolt with a paper towel and then apply a bit more clean oil. Screw the bolt back into the muffler, this time about 3-4 turns. Back it out. Clean it off, reapply oil and screw it back in about 5-6 turns. Repeat this process until you have cleared the residue from the muffler bolt holes.

Question: The muffler on the VMAX 46PRO and 52PRO has a long bolt that runs through the muffler from end to end. It has a nut on each end. This sometimes loosens up. How do I keep this bolt tight?

Answer: Install a lock washer and thread locker such as Pacer Z42 to each end of the muffler bolt and re-tighten the retaining nuts.

Better Answer: 2 Stroke engines vibrate by nature of their compression cycle and unbalanced reciprocating mass. If you have an unbalanced prop and/or spinner the vibration is even worse. This vibration is accentuated in the muffler due to it's low mass and the extended offset distance from the source of the vibration. Nuts and bolts in mufflers may loosen due to this high level of vibration. To prevent the nuts and bolts from loosening, balance your prop and spinner, install lock washers on the bolts and use Pacer Z42 thread locker on the nuts and bolts. Check frequently for tightness.

Question: I need the front portion of the Muffler only. All the rest of the muffler is fine... I just need the front portion. The 3 view diagram and parts list show the muffler itself and the rear portion but do not show the front portion. Is the front portion available as a part?

Answer: Yes it is part #VXR-464020F

Better Answer: Yes it is available as part #VXR-464020F. This does not include the muffler bolts, the long "hold it together" bolt, fuel nipple or muffler to manifold gasket or the muffler extension. These parts from the original muffler can all be transferred over to a new front portion.  

Question: I need the gasket that goes between the muffler and the crankcase exhaust manifold. This came with my engine originally and I have damaged it. It appeared to be made from thin aluminum. The 3 view diagram and parts list do not show this gasket.  Is the muffler to crankcase gasket available as a part?

Answer: Yes it is part #VXR-464000G

Better Answer: Yes it is available as part #VXR-464000G. It is stamped from thin aluminum and like most gaskets it must be handled carefully when installing.

Question: I am not using the muffler extension that came with my engine. I have installed the muffler directly to the engine crankcase exhaust manifold but I am having trouble getting the muffler to fit tightly. What can I do about this?

Answer: Place two washers under each muffler bolt and retighten the bolts.

Better Answer: When you are using the muffler without the extension, the bolt holes in some of the mufflers may not be quite deep enough to accomodate the full length of the threaded bolt. This is not common but has been found in some mufflers. The fix is easy. Simply install two small washers beneath the head of the muffler bolts to reduce the effective length of the muffler bolt. Re-install the muffler bolts and tighten snugly. Do not overtighten the muffler bolts or you will strip the muffler holes or the bolts themselves.

Question: Does the needle value in the VMAX 46PRO and 52PRO support the fitting of an extension rod to allow remote adjusting of the needle valve from a distance or from outside a cowl?

Answer: Yes it does. There is a hole in the big knurled end that accomodate a piece of piano wire or other stiff rod and a hex head set screw in the side of the needle valve to retain the rod.

Question: How much Nitro can I use in my VMAX 46PRO or 52PRO?

Answer: The 46PRO and 52PRO run well on 5% Nitro. The maximum recommended is 10%.

Better Answer: Using more than 10% nitro in the 46PRO or 52PRO is not recommended. Please review the instructions. Using more than 10% nitro will generate less power than 10% and generate more heat and lead to premature wear and engine failure. The VMAX 46PRO and 52PRO has been designed to give maximum power and longevity using 10% nitro or less.

Question: How much oil and what type of oil should  I use in my VMAX 46PRO or 52PRO?

Answer: The 46PRO and 52PRO should use fuel having no less than 18% total oil and the oil should be blend of synthetic and castor oil.

Better Answer: Using less than 18% oil in fuel supplied to a VMAX 46PRO or 52PRO will result in overheating, premature wear and engine failure. Using pure castor oil is OK. Using pure synthetic oil is NOT OK. The best oil mix is 19-20% total oil and the oil should be a blend of synthetic and castor oil.

Use commercial brand name fuel. Stay AWAY from home brew, old or brands of fuel that are not common in the marketplace. If facing a choice between a fuel that has a bit more oil and costs a bit more... go with the richer oil package for a buck or two more. A gallon of fuel lasts a long time and it is simply not worth risking what you are putting in the air to save a few bucks. Skip one burger a month and use the extra cash for good fuel!

Question: How much power do the VMAX 46PRO and VMAX 52PRO put out?

Answer: The approximate power output rating of the VMAX 46PRO and VMAX 52PRO are as follows:

• 46PRO 1.46HP @ 16000
• 52PRO 1.65HP @ 16000

Question: How much does the 46PRO weigh? Is the 52PRO heavier? Is the 52PRO bigger? What are the dimensions of each?

Answer: The 46PRO and 52PRO are the same size and they both weigh as follows:

• Engine without muffler 13.6 oz (386 grams)
• Muffler 4oz (114 grams)
• Engine with Muffler 17.6 oz (500 grams)

These weights are accurate to within +- 5%.

Better Answer: The 52PRO is based on the 46PRO. It uses the same crankcase. They are the same size physically and are bolt compatible. If a 46PRO fits, so will the 52PRO. The crankcase of the 52PRO has been bored out. The cylinder and piston of the 52PRO are slightly larger in diameter. The result is that the two engines are exactly the same physical size and weigh practically the same with the 52PRO weighing 1-2 grams less.

For people who like to buy in big volume... a case of 24 engines weighs approximately 39 lbs (18 kg) and measures 20.5x15x15in. (807x381x381mm). Case volume is 2.67 cubic feet (.1171 cbm).

The Operating Manual that comes with the each engine includes an Exploded 3-View and a case dimensions chart for reference. This manual can also be downloaded from http://www.richmondrc.com/vma/vmax.htm.

Question: I have inadvertently adjusted the low speed mixture to the point that I am not happy with where I ended up. I want to return to the original factory setting and then work from there but I forgot to take note of the original setting. Can you tell me the original factory setting for the low speed mixture screw on a VMAX 61PRO?

Answer: Yes. Here are some tips to help with this.

a) Please review carefully the owners manual that came with your engine. Look for the section related to adjusting the low speed mixture. As of  20071201 this was sections 6.9 and 6.10. Read these sections over carefully and them read them again. Do not proceed until you have read these sections AND have met the conditions stated therein. In particular note that you should not be mucking with the low speed mixture screw until you have broken in the engine to the degree specified in the owners manual. Mucking with the low speed mixture screw too early is a waste of time and will cause you a bunch of grief and aggravation for nothing.

b) After reading the sections of the owners manual related to adjusting the low speed mixture, if you want to return the low speed mixture adjustment screw to its original factory location, please do the following:

• Rotate the screw clockwise so that it moves into the carburetor while counting the rotations until the screw becomes tight to turn. Do NOT OVER TIGHTEN... once the screw is snug and does not want to turn, STOP. This is not a tractor and there are no points given for brawn here... stop turning when the screw starts to get snug.
• Now turn the screw counter-clockwise so that it starts to back out of the carburetor.
• Rotate the screw and count one and a quarter (1-1/4) full turns for a 61PRO

Thats it. You are more or less back to the original factory setting.

Question: What are the dimensions of the VMAR Pitts Style Mufflers?

Answer: Please see the attached PDF's of the labels from the packaging. These labels contain a diagram and the specifications for each muffler. The MF126 is the 45 size muffler... the MF6090 is the 60-90 size muffler.

Question: Do the VMA Pitts Style Mufflers fit all .46-.52 Engines?

Answer: No

Better Answer: The VMA Pitts Style Mufflers fit the VMAX .46PRO and the VMAX .52 PRO engines and most popular engines of this size. They do not fit some of the off brand engines that do not have a standard exhaust manifold.

Question: What are the dimensions of the VMAR Pitts Style Mufflers?

Answer: Please see the attached PDF's of the labels from the packaging. These labels contain a diagram and the specifications for each muffler. The MF126 is the 45 size muffler... the MF6090 is the 60-90 size muffler.

Question: Has the VMAX Pitts Style Muffler been upgraded? If so, what changed and how can I tell an upgraded muffler from earlier production?

Answer: Yes in mid 2004 the VMAX Pitts Style Muffler was upgraded. These are sold as stand alone mufflers to fit most popular 46-52 and 61 size engines AND provided at no charge per various special offers.

Here is what changed: 

• The fit and finish was greatly improved.
• The production of the crankcase mounting flange was moved to an automated process to improve the consistency of flatness, fit, spacing between mounting holes and the bolt hole threads.
• A new high temperature plating process was implemented.
• The exterior color was changed from black to silver.
• In early 2005 a logo was impressed into the product.