Rear Exhaust HT instructions

WARNING: Use NGK CMR7H spark plug, gapped to .025.
DO NOT USE THE CHAMPION RZ7C SPARK PLUG, severe engine damage will result. Only use the NGK CMR7H spark plug, gapped to .025

WARNING: Do NOT use prop blast pickups, use a double water pickup rudder only. Make sure the smallest hole through this rudder is 1/8". If yours is smaller, drill it out to 1/8" with a long drill bit. Do not Tee a single pick up rudder to the 2 lines in.

WARNING: The 2 water lines in are below the exhaust port.  The 3 water lines out are on top of the cylinder.   DO NOT USE any 90 degree fittings either coming in or going out.

WARNING: Do not change the hard plastic hose from the carburetor to the engine crankcase. Do not use a 90 degree fitting of any kind in this line.

WARNING: Always set your boat up so you can kill the engine with the radio. You will need a kill switch connected and activiated by a 3 rd channel to kill your engine reliably. Simply closing the carburetor will NOT kill the engine reliably, you MUST have a 3 rd channel kill switch installed. Some radios have a feature that allow you to mix the 3 rd channel with your throttle channel, this will allow you to engage the kill switch through your throttle trigger. Read your radio programming instructions and understand them. DO NOT operate your boat until you are positive you can kill the engine reliably with a kill switch of some type. You need to contact the kill switch manufacturer/supplier and get the correct kill switch that is compatible to your particular radio. For example, you can review the gas kill switch at A good  kill switch will also be a fail safe if you have radio issues. Shop for quality, not a cheap price.

This engine uses the new style pipe. We use 2 o-rings, the outer o-ring may start to extrude out the flange fairly early on but there is nothing wrong with the o-ring and it doesn't need replacing until the flange starts leaking oil.  This usually takes a while before it starts happening. After running for the day, remove the flex from both the header and the body. Dry the flex piece off and recoat inside and outside where it plugs into the coupler with Anti-Seize. Failure to do this will result in a permanently rusted in flex coupling. Go very sparingly with the Anti-Seize or it will make a mess all over the inside of your boat. Some people just take the flex out and use Rost off on the flex when they are done for the day and have had good results. Do what works for you but use common sense, you don’t want the flex joint rusted in your pipe or header, that is the bottom line.

If your flex coupling is leaking oil, this is because you are running your engine way too rich, or you have way too big of a prop on the engine, or you are just idleing the engine around slow and easy. The engine was not made to be a trolling motor. It was intended to be run reasonably fast. Some oil may leak after you first fire up your engine and it’s had Rost off in it and it is still running rich but this should go away in just a few laps.

IMPORTANT: Do not replace your flex joint with a piece of solid tubing. This defeats the whole purpose of the flex joint and it can very likely lead to pipe cracking and possible radio interference. Your flex joint will not leak oil all over the boat when the engine is properly tuned and the boat is properly set up.


Your cylinder is marked with the type and number of base gaskets that your engine requires, there are Brown (BR) , Black (BLK) and White (WH) base gaskets.

Your particular engine requires ____ Brown, ____ Black and ____ White base gaskets. Put the brown or black one next to the cylinder and the white base gaskets next to the cases. You should check your deck height and change the required number of base gaskets as needed if you replace the piston and/or the crankshaft. How to check your deck height is below.


You need to set the deck height very carefully, this is where the white base gaskets come in. If you need the white base gaskets, put them next to the engine cases and put the brown or black base gaskets next to the cylinder casting. The deck height should be set to .010 to .012 inches. To measure this, you need to have a dial indicator that will screw into the spark plug hole. You put the cylinder on with no base gaskets at all, bring the piston up until it hits the head button and stops. Now set the dial indicator to zero with the piston hitting the head button. Now very carefully take the cylinder back off without bumping the dial indicator, put one brown base gasket on and tighten the cylinder down. Be sure the gaskets have been soaked with Rost off. Now rotate the piston up and read your deck height on the dial indicator. Work with the different gaskets to get the correct deck height.

Your engine has already been broken in and thoroughly tested here on our water brake dyno. No further break precautions are needed. Mix the oil the same as you would for regular running, 10 ounces of Honda HP2 oil to 1 gallon of 87 octane regular pump gas. Do NOT use premium or any kind of race fuel with this model engine. This will not hurt the engine, but you won’t get as much power as you will get with 87 regular.

DO NOT RUN COLEMAN LANTERN FUEL, this WILL hurt the engine because of detonation.

If you get water in the motor, do not run it again until you take the cylinder off and flush it out. It is not worth having the grit tear up the motor that gets into it. With the new base gasket system this makes it easy to do. Remove the 4 base bolts and flush out the water with carb spray until no water is evident. Reoil everything and reinstall the cylinder. If you do this quickly enough, a lot of times you can reuse the same gasket if you do not take to long. If gasket gets hard or curls up install new one. Spray gasket with WD40 on both sides and install. Follow same procedure as before with seating a new gasket. After end of day running use ROST OFF from WURTH products and spray into motor until it runs out everywhere. Leave this way until you run again. When you run again, remove the sparkplug from motor and pull rope to remove excess ROST OFF from motor. Reinstall sparkplug and run like normal. ROST OFF’s phone number is 1-800-987-8487 and the partnumber is 08902 . You will have to take it in case quantities of 12 per case. This is a very good product and you will use it in many things.
If you run in salt water, be sure to remove head button and dry out the 10 bolt holes in the cylinder and reapply anti-sieze to the bolts once you are done running for the day. Do not let the engine sit overnight after it’s been running in salt water without doing this. Otherwise the bolts will corrode in and removal will be difficult if not impossible.

Note there are no metric threads on the parts supplied in this kit except the spark plug hole. Note: The sleeve is no longer removable as it was in the older engines. It is heat shrunk in and removing and reinstalling it will ruin the tolerances. You can send the cylinder casting with the sleeve in it back to us to have a new sleeve installed. This is a little more inconvenient than the old slip in sleeves but the end result is a much better product. Bearings now come pre-installed so you don’t have to follow the procedures below, but if you want to change the bearings, heat the cases up to drop the bearings out and then follow the instructions below to put them back in. When installing the clip in the case, make sure that it is pushed outward all the way or the bearing won't go all the way down and you won't have any crank end play. Use only genuine ZENOAH bearings. Do not use any other bearings besides these. Failure to do so will result in little or no crank end play. Heat cases to 350 Deg. Fahrenheit and drop bearings in. DO NOT PRESS BEARINGS IN COLD CASES. Be sure the bearings are all the way down and not cocked in the bearing bores. Put some grease on the seal lips for seal lubricatrion. Put a little gear sealant (Mopar #82300234, you can find this at Chrysler, Dodge or Jeep dealers. Use this sealer anywhere on the engine that sealer is required. This sealer won’t dissolve in gasoline and it is easy to clean up. This stuff is worth going after and once you get it you will use it on everything) between the case halves and bolt together. Be careful not to pinch the rod in the pulse port slot when assembling cases. Use a little bit of gear sealant on the ignition plate to case surface. Put case in the vise, but do not crush it. Use a good fitting #2 screwdriver to tighten the screws while pushing down on them. Either use a screwdriver like a Snap-On brand or another style that has a hex on its shank to put a wrench on and tighten it. A channel lock plier grabbing around the handle also works in a pinch. Check to make sure that there is no burrs or metal shavings in the wrist pin circlip holes. (NOTE: USE A 260 WRISTPIN IN THE MOTOR) Install piston with the ring locating pin towards the intake port. Apply oil on cylinder, piston, wrist pin bores and all bearings. DO NOT assemble dry. Install head button o-ring into head. Make sure the o-ring is in the groove and does not get pinched between the sleeve and the head. Be sure and use antiseize on the bolts that hold the head down. Install head button and tighten down. Check and make sure that there are no burrs in o-ring groove in the water cover. Install o-ring into water cover groove. Apply a little bit of oil on the o-ring. Add gear sealer to outer edge of the water cooling cover. Cylinder was designed with the intake port on the right side of the motor when viewed from back of boat. DO NOT TRY AND REVERSE THE CYLINDER. Spray base gasket with WD40. Give it a few minutes to soak in. Install base gasket on case making sure pulse port slot lines up. DO NOT USE ANY SEALER IN THIS AREA. Install cylinder using 8-32X5/8 bolts, Belleville washers and the 5/16X.050 washer. Belleville washer goes under head of screw. Then the 5/16X.050 washer goes under that. Tighten down cylinder base bolts using a L-shaped wrench to do this that has been ground shorter to fit in this area. You may need to use a ball driver. After each run check the base bolts. Continue to check until fully seated and will not tighten any more. Gasket is now seated and you should continue to keep an eye on them, but they should not loosen as quickly as they will with a new gasket. (The cylinder base bolt loosening and other vibration problems can be helped dramatically by adding the optional output flywheel.) The 2 water fittings on the base of the cylinder are for the water in. The 3 fittings on the water cover are the water out, they go on the pullstarter side. Do not reverse the cover to make more clearance under your cowl. If you reverse this your engine will overheat and it will do a lot of damage. If you need more clearance for water outlet lines use Aeromarine #2004 fittings. Use 3 water lines to dump overboard. Use blue loctite on the crankcase pulse port holes that you do not want to use. Use the set screws noted in the hardware list to do this. Use the 2 #10 washers under the head of the intake manifold mounting bolts. Some grinding on manifold in the corner will have to be done to clear the washers. Use blue Loctite on the screws that mount the intake manifold. Be sure and run Honda HP2 motorcycle oil at 10 oz. per gallon of oil. When it comes to the oil, do not think that you know it all and use something else or some other mixture. If you want to run a different oil because you run it in one of your other engines, then change the oil for your other engine, not this one. After all, you probably paid more for this engine than the other engine anyway. Do not call us wanting to discuss different oil or oil ratios. We do not want to talk about it. As far as we are concerned, this is the only oil and the only ratio you can run. NOTE: If you use Aeromarine drive couplers, cut (shorten) so there is .080 behind the hex. If you don’t do it, it will interfere with the output crankshaft seal and destroy the seal. If you use any other collet, check for clearance.

If you want the repairs done correctly and the latest revisions, you need to send your engine back to us. We don’t recommend having other shops work on your Quickdraw because they don’t have the equipment it takes to do it correctly. That is because they don’t need that equipment to work on a Zenoah

The carb settings following are starting points for the High Torque engine:

For the WT668 it is 1-7/8 on the low and 5/8 to 3/4 on the high

For the WT603 it is 1-7/8 on the low and 1 to 1-1/8 on the high
For the WT644 it is 1-3/4 on the low and from 7/8 to 1 on the high
For the WT488 it is 2 on the low and 1/3 to 3/4 turns on the high
For the WYK33 it is 7 turns on the low and 1-3/4 on the high

When setting your carburetor, you must realize that the low speed needle needs to be set so that the engine sounds rich and dirty when it is on the stand.  It will even sound this way when it is in the water when you are running at low speeds.  If you try to set the low needle so the engine is real crisp and responsive, in other words it sounds really good on the stand, this is too lean of a low setting and it will bog in the water when you try to accelerate.  For the most part you can set your low needle to our recommended settings and just leave it there and not adjust it at all. 
 The High Speed needle is another story.  You will need to move the high needle to find your best performance.  If you get the high needle too lean, you will have less mid range torque. A slightly rich setting gives your engine more torque. Too lean of a setting on the high speed needle will also make the engine flatten out on the top end.  You really can't hurt the engine by over leaning the high speed needle, it will just flatten out and have less performance if it is too lean. 

The low speed needle of the WYK33 carburetor is in the center of the carburetor barrel.  Use a small precision flat blade screwdriver to adjust it. You must use Loctite #222 on the low needle threads. Do not use any other Loctite other than #222.  If you do you may never be able to move the low speed needle again.  Make sure you clean all of the threaded surfaces with contact cleaner or carburetor cleaner and dry them before you apply the Loctite. If  you want to adjust the low speed needle after the Loctite has dried, only move it a little bit in the direction you want to go. Do not run it all the way to the bottom and then back it out, this will wipe all of the #222 Loctite off and the low needle will be loose again. All modified WYK33 carburetors and replacement bored out barrels come from us already Loctited and the low needle is set at 7 turns out. 
With this carburetor, you can set your low speed so the engine is fairly clean and responsive.  Don't over do this, lean the low speed needle so the engine just cleans up and no more on the low end.  If you get the low too lean, this carburetor will bog also (see info above on the butterfly carburetors).  You also may have difficulty shutting the engine off if the low needle is too lean.  Usually opening and shutting the carburetor quickly will allow the engine to quit.  If you want to have a reliable shut off, hook your throttle linkage to a kill button.  You should have the kill switch hooked up to your radio anyway, it is the safest thing to do.  Setting the high needle has the same characteristics as the butterfly carburetor info above.  See below for instructions for Loctiting the low speed needle.

The low speed needle of the WYK33 carburetor is in the center of the carburetor barrel.  Use a small precision flat blade screwdriver to adjust it. You must use Loctite #222 on the low needle threads. Do not use any other Loctite other than #222.  If you do you may never be able to move the low speed needle again.  Make sure you clean all of the threaded surfaces with contact cleaner or carburetor cleaner and dry them before you apply the Loctite. If  you want to adjust the low speed needle after the Loctite has dried, only move it a little bit in the direction you want to go. Do not run it all the way to the bottom and then back it out, this will wipe all of the #222 Loctite off and the low needle will be loose again. All modified WYK33 carburetors and replacement bored out barrels come from us already Loctited and the low needle is set at 7 turns out. 


Can I advance my ignition timing on my High Torque?

No, not on a High Torque engine. Your red source coil should be in the set of holes that is all the way to the right as you are facing the red coil on a side port engine. On the rear exhaust High Torque the red source coil should be at the top set of holes when facing the red source coil. The advance set of holes are +5 degrees and +10 degrees. If you go to even the +5 degree advance setting, it will cause detonation and will eventually crack the head button. The old Hi Rev series engines used the +5 degree setting. The High Torque engine set on the +5 degree setting will have less low end torque and when it comes on the pipe it will hit harder but it will not make any more power, it will just cause a power band that is harder to drive and actually run slower. We continue to leave the advanced timing setting holes in the ignition plate in case we make a future change that does work better with the advance ignition timing. By doing this, the customer will not have to buy a new ignition plate if we make a modification in the future that works good with advance timing.

Wavier of Liability and Indemnification Agreement
Because we have no control over the application or installation of our products, the purchaser by placing an order and accepting products from us, agrees that all materials purchased will be used solely at purchaser’s risk and that purchaser will indemnify and hold Quickdraw, it’s owners and employees, free and harmless from all loss, liability or damage resulting from claims brought by reasons of any alleged failure or defect or any part or parts supplied by us. It is the responsibility of the owner/operator to determine the suitability and proper installation of any of our products.