MERCURY 3.5HP OUTBOARD
Model # 3.5ML
|Shaft Size:||20" (Long)|
|Drive Type:||Tiller Handle|
|Gears:||F - N - R|
List Price: $1200.00
Save: $135.00 (11%)
Free Shipping (lower 48 states)
No Sales Tax (except TN)
5 Year Mercury Warranty
Go anywhere with portable power. Mercury 3.5hp models include all 2.5hp features plus enhanced features such as a larger carburetor for increased performance and 15" or 20" shaft length options.
The Mercury 3.5 is a great choice of power for canoes, small tenders and inflatables. A long shaft model is popular for mini-pontoon boats and smaller sailboats.
At just 40 lbs, Mercury designed the 3.5 to be compact and lightweight. The ergonomic carry handle evenly balances the engine for easy transporting.
- • Integral Fuel Tank (0.3 gal)
- • Owner's Manual
- • Mercury 5-Year Warranty
- • Propeller (Composite)
- • Mercury 4-Stroke Oil
- • Tool Kit
|Horsepower @ Propeller:||3.5hp|
|Engine Type:||4-Stroke, 1-Cylinder, OHV|
|Full Throttle RPM Range:||5000-6000|
|Displacement:||85.5 cc (5.22 cubic inches)|
|Bore and Stroke:||55 x 36 mm (2.16 x 1.42 inches)|
|Fuel Induction System:||Overhead Valve (2-valve pushrod)|
|Ignition System:||Digital CD Ignition w/Electronic Spark Advance|
|Fuel System:||Single Venturi Carburetor|
|Cooling System:||Water-Cooled, Thermostatically Controlled|
|Alternator:||Not available on 3.5hp models (4hp & up only)|
|Gear Shift:||Forward-Neutral w/ 360° Steering for Reverse|
|Lubrication:||Slinger Splashing System|
|Oil Type:||SAE 10W-30 (Mercury 4-Stroke Outboard Oil)|
|Oil Capacity:||10 fl. Oz. (300 ml)|
|Fuel Type:||87 Octane (up to 10% ethanol content)|
|Fuel Tank (integral):||0.3 US Gallon (0.95 liter)|
|Fuel Range:||Approximately 45 Minutes Run-Time @ Full Throttle|
|External Tank Ready:||Not available on 3.5hp models (4hp & up only)|
|Warning System:||Over-Rev Protection|
|C.A.R.B. Rating:||Ultra-Low Emission (3-STAR)|
|Propeller:||7.4" Diameter x 7.0" Pitch 3-Blade Composite|
|Shaft Length:||20" Long Shaft (shaft size help)|
|Weight:||40 lbs (18 kg)|
Mercury Marine 5-Year Warranty (included)
Mercury outboards are backed by Mercury Marine's 5-Year Warranty. Warranty service is available through any U.S. authorized Mercury Marine dealer or service center.
3 - 4 business days
4 - 5 business days
5 - 6 business days
6 - 12 business days
Business days are Monday-Friday, excluding holidays. The above transit times are estimates only and are not guaranteed.
Orders typically ship within 1 business day or less, and tracking information is provided via email within 24-48 hours.
- Shaft Length: How do I measure?
- Engine Oil: Do 4-stroke outboards come with engine oil pre-filled?
- Oil Type: What type of oil should I use in my 4-stroke outboard?
- Transport/Storage: Can a 4-stroke outboard be laid on its side?
- Lower Unit Oil: Do outboards come with lower unit oil pre-filled?
- Fuel Type: What type of gasoline should I use in my outboard?
- Fuel Consumption: How much fuel is used per hour at full throttle?
- Electric Start Models: Is back-up manual start also included?
- What is the smallest outboard that offers electric start?
- 12V Alternator: How much is a 12V Alternator kit for my outboard?
- BigFoot 9.9hp Models: What is a "BigFoot" model outboard?
- ProKicker Models: What is a "ProKicker" model outboard?
- Remote Models: What is a remote control model outboard?
- Remote Models: Why can't remote control models be shipped?
- Saltwater Use: Are Mercury outboards salt-water rated?
- Freshwater Flush: How do you recommend I flush my outboard?
- Break-In: What is the break-in procedure for my new outboard?
- Warranty: How does the Mercury Marine warranty work?
- First Use: Is there anything I need to do before using my outboard?
- Placing Your Order: What are the benefits of ordering online?
- Payment Methods: What types of payment do you accept?
- Free Shipping: Is shipping free within the lower 48 states? AK/HI?
- Shipping Time: How long will it take for my outboard to arrive?
- Tracking Info: How is tracking information provided?
- Freight Damage: What do I do if my outboard is damaged in transit?
- Shipping Outside U.S.: Do you ship outside the U.S.?
- No Sales Tax: Do you collect sales tax outside of TN?
- Tennessee Orders: Is tax added if I pick-up my outboard in TN?
- Warranty Registration: How is my warranty registered?
- Trade-Ins: Do you accept trade-ins?
- Used/Non-Current: Do you sell used or non-current outboards?
- Our Location: Where is your dealership located? (Cookeville, TN)
If mounting directly to a boat transom: Measure from the top of the transom down to the bottom of the hull or keel (lowest point). Measure the area of the transom directly where the engine will be mounted. See diagram below.
If using an auxiliary mounting bracket: With the bracket in the down position, measure from the top of the bracket's mounting surface down to the bottom of the hull or keel (lowest point where engine will be mounted). Tip: For most auxiliary applications, it is possible to use a longer shaft length than what is called for, provided there is sufficient clearance when the engine is in the up position. This can be especially useful in heavy seas.
If measuring an existing outboard: Measure from the inside top of mounting bracket down to anti-cavitation plate above propeller (this is the largest plate/fin directly above the propeller). See diagram below.
|Height Measurement:||Recommended Shaft Length:|
|14” – 17.25”||15” Shaft (Short)|
|17.25” – 19.5”||Varies by application – email us|
|19.5” – 22.5”||20” Shaft (Long)|
|22.5” – 27”||25” Shaft (Extra-Long)|
NO! Four-stroke outboards are not shipped with engine oil pre-filled. You must add oil to the crankcase prior to use. Portable Mercury 4-stroke outboards include oil in the box - measure carefully to avoid overfilling.
SAE 10W-30 Mercury Four-Stroke Oil (included with new engine purchases) or a premium quality SAE 10W-30 engine oil, preferably marine grade when available.
|2.5hp and 3.5hp||10 fl oz. (300 mL)|
|4hp, 5hp and 6hp||15 fl oz. (450 mL)|
|8hp and 9.9hp||27 fl oz. (800 mL)|
|15hp and 20hp||1 qt. (1000 mL)|
NOTE: With four-stroke outboards, oil is added directly to the engine crankcase. Four-stroke outboards use straight gasoline in the fuel tank (no oil mix). Mercury recommends that engine oil be changed every 100 hours or once yearly, whichever occurs first. See your owner's manual for detailed information on how to fill and change engine oil.
Yes. Portable Mercury 4-stroke outboards can be laid on their side, but they must be laid on the proper side. Your outboard includes a picture (decal) on the engine itself indicating which direction the engine can be laid. Please see owner's manual for additional information on transporting and storage of your outboard.
Yes. Lower unit gear oil is pre-filled by the factory, however, you should check prior to use to ensure proper level. To replace or add lower unit oil we recommend any SAE 80 or 90 weight oil. For additional information, see your owner's manual on how to check or change the oil in your lower unit.
Mercury outboards require minimum octane rating of 87, however, using gasoline with an octane rating of 89 or higher is recommended when available.
Fuels containing up to 10% ethanol are acceptable for use in all Mercury outboards. Use of a fuel stabilizer is highly recommended to help maintain fuel. Fuel stabilizers include oxidation inhibitors and water absorbing agents which help prevent corrosion, fuel degradation and gum formation in your engine's fuel system.
The charts below will help you determine what type of fuel consumption you can expect from portable 4-stroke Mercury outboards.
Please Note: Many factors affect fuel consumption and therefore figures listed below are approximate only will not necessarily be what you will obtain. Factors such as weight, hull shape, hull condition, water conditions, etc. can drastically affect the amount of actual fuel consumption.
The following charts show the approximate fuel consumption of each portable model:
|Approximate Fuel Consumption Chart
Mercury Outboards (current models)
Yes. All tiller model 4-stroke Mercury portables with electric start also include the standard manual thru-cowling pull cord. You do not have to remove the cowling or do anything special to manually start the engine. No more missed boating trips due to a dead battery. All electric start models also feature a 12V charging system as standard pre-installed equipment so engines can be manually crank started and the charging system will recharge a dead or weak battery.
The 8hp is the smallest Mercury outboard offered with an electric start option.
All portable outboards with electric start also include a 12V charging system pre-installed and full through-cowling back-up manual rope start (just as found on manual start models) as standard equipment.
What does it do?
The 12V charging system allows the user to charge a 12V battery. With this option installed, the outboard engine will send charging current to the battery when the outboard engine is running. The output is variable based on engine RPM.
Who needs this option?
Anyone who has a 12V battery in their boat (for lighting or other accessories) and would like an alternative or supplemental charging method.
NOTE: The 12V Alternator/Charging System is an option only and is NOT required to operate the outboard. This feature can be added to manual start models from 4hp - 20hp. On 8hp - 20hp electric start models, this feature is standard equipment and no additional purchase is necessary. This feature is also standard on 6hp 25" Sail Pro models.
How much is a 12V Alternator/Charging kit for my outboard?
We offer genuine Mercury 12V alternator charging systems that include a rectifier which provide your outboard with the ability to charge a 12V battery should you have the need or desire to do so.
MANUAL START MODEL OUTBOARDS Optional 12V Charging System Cost:
4, 5, 6hp* = $229.99 w/Free Shipping
8, 9.8hp = $229.99 w/Free Shipping
15, 20hp = $189.99 w/Free Shipping
For manual start models, the add-on 12V charging system requires installation (electric start models include the system pre-installed from the factory). We recommend professional installation as in most cases the flywheel must be removed to install the charging coils. If you could not or did not wish to complete the installation yourself, any marine tech should be able to complete this service for 1 hour of labor. We also offer installation of the system for an additional charge of $59.99.
ELECTRIC START MODELS: 12V CHARGING SYSTEM IS STANDARD
Electric start model engines automatically come standard with the 12V charging system pre-installed from the factory. No assembly is required. You simply connect the 8.2 ft positive/negative electric start battery leads (provided) to your battery.
Mercury 9.9 BigFoot models are designed specifically to develop the power, thrust, and control demanded by heavier boats such as in sailboat and trolling/kicker applications. A larger, deeper lower unit with a low 2.42:1 gear ratio is combined with a 20% larger high thrust propeller to deliver additional thrust and maneuverability. BigFoot lower units also have an oversized anti-ventilation plate which helps prevent air from being drawn into the propeller, further enhancing performance and increasing efficiency. BigFoot models are available in 20" and 25" shaft lengths (9.9hp models only).
Four-Stroke 9.9 and 15hp ProKicker models are designed specifically as auxiliary trolling motors (often called "kicker" motors). Standard ProKicker features include a compact power tilt system, high-thrust four-blade propeller, heavy-duty transom brackets and sporty decals. Automatic self-centering straps holds the engine straight, eliminating the need for additional hold-downs when running in rough boating conditions or while trailering (standard on all tiller ProKicker models). Available in 20" and 25" shaft lengths.
9.9 BigFoot ProKicker models include all features listed above plus a larger and deeper lower unit with an over-sized anti-ventilation plate. The BigFoot lower unit also includes stronger gears, bearings and shafts and a low 2.42:1 gear ratio which offers improved handling at low speeds and best-in-class slow trolling speeds.
A "remote control" outboard is one that is equipped with remote steering, throttle, and shift controls. Due to manufacturer restrictions we are not able to ship any HP remote control model outboard. We can only ship tiller handle (hand driven) models up to 20hp.
Mercury Marine does not permit shipment of any remote model engine (any HP remote) or any engine above 20hp.
We offer and ship tiller models only, up to and including 20hp models.
Yes. All Mercury outboards are designed for saltwater and freshwater use. These outboards are known for their long-term durability over years of demanding saltwater use.
For maximum durability and corrosion protection, all Mercury outboards feature:
- High Grade Marine Alloy Construction
- Stainless Steel Water Pump Housings
- Zinc Coated Internal Water Passages
- Sacrificial Zinc Anodes
- Exclusive Multi-Layer Protective Coating
Below is the recommended flushing procedures for Mercury 4-stroke portable outboards:
Caution: To avoid injury in the event of accidental starting, be sure to remove the propeller and the stop switch lanyard cord from your outboard before proceeding.
Important: All Mercury outboards are water cooled; running your outboard without an adequate source of cooling water will result in severe damage to your outboard.
2.5, 3.5, 4, 5, & 6hp:
For smaller outboards, the simplest way to flush your outboard is by using a large container of water (bucket, pail, barrel). Be sure the container is large enough to completely cover the water intake ports on the lower unit of the outboard. Also be sure that the container is wide enough so that no part of the motor will touch the sides/bottom of the container. Securely mount your outboard on a sawhorse or other sturdy device that will allow safe operation of your outboard. You may also use an optional "flushing plug", see below.
8hp - 20hp:
For 8hp-20hp outboards we recommend you use a motor flusher ("ear muffs"). This type of motor flusher is easy to use, inexpensive, and available at virtually all marine retailers. This device attaches to your garden hose and clamps on to your outboard's lower unt, covering the water intake ports. Turn the garden hose on fully prior to starting the engine. Make sure the "ear muff" motor flusher is firmly in place and correctly positioned over the water intakes on your lower unit. (Note: the "ear muff" motor flusher will not work on outboards below 8hp)
Run your outboard at normal idle speed for approximately 5 minutes to allow the engine to warm up and to ensure your outboard is thoroughly flushed with clean water. DO NOT rev up the engine as this is not necessary for flushing and could cause damage to the water pump.
Flushing Plug Attachment:
The flushing plug attachment is available for all outboards ($19.99). It is a bit cumbersome to use and requires removal of a water bolt on the engine. Once the water bolt is removed, the flushing attachment can be used. After flushing, the flushing attachment is removed and the water bolt is re-installed. When using the flushing plug method, the engine should NOT be operated while flushing using the flushing plug attachment.
The break-in procedure is included in your owner's manual. Engine break-in consists of maintaining lower RPM levels and varying the RPM's for the first 10 hours of use. Break-in should be done under a load (on your boat, not at home in a container of water). Correct operation during the break-in period will prolong the life of your new outboard and will ensure optimum performance.
Mercury Marine 3-Year Warranty (included)
Mercury outboards are backed by Mercury Marine's 3-year warranty. Warranty service is available through any U.S. authorized Mercury Marine dealer or service center. If you need help locating a service center in your area, please email us and include your zip code. These service centers can also provide service after the warranty period.
Mercury outboards undergo an extensive factory inspection, including a tank test prior to being crated. While other manufacturers only spot check some engines, Mercury Marine test every portable engine. This ensures the highest level of quality and customer satisfaction upon delivery.
Engine oil must be added prior to use. The engine oil is drained prior to shipping. When your new outboard arrives, you simply add engine oil (see owner's manual for oil type and capacity for your model). The lower unit gear lube is pre-filled from the factory. No assembly is required. Even the propeller is pre-installed for your convenience.
If you purchase an electric start model, your outboard will include battery leads pre-installed from the factory (battery not included). You simply connect the battery leads to your battery.
Read the owner's manual carefully prior to operation. The owner's manual contains important information regarding the break-in period, safety and proper use of your outboard engine.
- Online checkout is quick, convenient, and 100% secure
- Order anytime: 24 hours a day, 7 days per week!
- Receive an instant order confirmation
- Online orders are sent directly to our warehouse for priority processing
- Tracking information is automatically emailed when order is shipped
Credit Cards: VISA, MasterCard, Discover, Amex
Check Payments: Personal Checks, Money Orders, or
Bank Checks (cashier's checks) are accepted.
All check types and money orders are subject to a clearing period of 5-7 business days prior to order shipment.
Prior to mailing a check or money order,, contact us by phone to place your order. You will receive an order confirmation number which must be included with your check/money order..
Yes! We offer FREE SHIPPING within the lower 48 states with no hidden fees.
Shipping to Alaska and Hawaii is additional. For AK/HI shipping cost, visit the product page for the specific model you are interested in and click the "Shipping Information" tab.
We do not ship outside the U.S. per mfg. restrictions.
Shipping time will vary by location (typical transit time is 3-7 business days inside the lower 48 states). Select the "Shipping Information" tab at the bottom of each outboard model page to determine the estimated transit time to your location. Please note that shipping times provided are estimates only and are not guaranteed.
Tracking information is provided via email, typically within 24-48 hours of your order being placed online. The tracking information will be located on your final receipt/invoice.
Our outboards are very well packaged from the factory. All outboards are shipped in the factory crate and very rarely receive damage during transit. Less than 2% of our outboards receive damage during transit. All outboards are fully insured. If your outboard has received severe damage (engine is visibly exposed from packaging) refuse the package and contact us immediately. If your engine has received minor damage (such as a crack in cowling or other minor damage) you may accept shipment (if you wish) and contact us immediately to receive a replacement of the damaged part and/or file a claim with the carrier. Please retain all packaging.
NOTE: If your engine is being delivered via motor freight (truck freight), be sure to note crate or engine damage on the bill of lading when signing for the shipment.
No. Unfortunately, we are only able to ship inside the U.S. 50 states. We are not able to ship outside the U.S. per manufacturer restrictions. Sorry, no exceptions.
NO SALES TAX is collected for shipments outside of TN. (TN residents add 9.75%)
Yes. Orders that are picked up at our location or shipped inside TN are subject to 9.75% sales tax.
For your convenience, we automatically register your warranty electronically. No further action is required and you do NOT need to complete any paper registration cards that may be included in the box.
No. Sorry, we do not accept trade-ins outside of our own local market. Due to shipping costs, it is nearly impossible to run a successful trade-in operation. Selling your engine outright will generally yield higher returns and there are no wasted shipping costs.
No. We sell only brand new current production model outboards. On rare occasion we may have a non-current model during a program changeover. If a non-current model became available, a sale would be clearly posted on our home page.
202 Dragon Drive
Dickson, TN 37055