How should I select the propeller for outboards?
Propellers have two basic dimensions; diameter & pitch. Diameter is the distance measured across the propeller hub line from the outer edge of the circle that is made by the propeller’s blades during rotation. Pitch is the distance that a boat will travel if rotated one revolution without any slippage. When describing parameters of a propeller both the diameter and pitch are given. The diameter is referenced first and the pitch is second. For example, a 11″ x 9″ propeller would have a 11-inch diameter and a 9-inch blade pitch.
Theoretically, a propeller with an 11-inch pitch, when rotated one full turn, would advance a boat 11 inches through the water. In reality, an 11-inch pitch blade will not advance a boat 11 inches with one full turn. This variance is referred to as slippage. In general, changing to a higher pitch prop will increase your top-end speed but reduce your acceleration (reduce your “hole-shot” power). On the other hand, decreasing the pitch will increase your hole-shot but sacrifice some of your top-end speed. If the hole-shot speed is important to you, for example, when pulling water skiers, you would choose a lower pitch prop, which would sacrifice some of the top-end speed but it would increase your hole-shot speed for the skiers to get up faster.
UNDER NO CIRCUMSTANCES SHOULD YOU EVER USE A PROPELLER WHICH WILL ALLOW YOUR OUTBOARD TO OPERATE ABOVE THE OUTBOARD’S RECOMMENDED MAXIMUM RPMS! Remember that in any application, discrepancies in performance can result due to the different boat hull designs, the final carrying load and your particular needs. NOTE: It is highly recommended that the outboard be checked with a tachometer to ensure that the engine is operating within the correct MAXIMUM RPM RANGE.
How can I tell what shaft length my outboard needs to be?
Measure from the top of your transom to the bottom of your keel. If it is between 15″ to 17″ you’ll want to choose a Parsun outboard motor with a “short” shaft. If it is between 20″ to 22″ you’ll want to choose our “long” shaft outboard. Parsun outboards shafts are measured from the bottom of the engine mounting bracket to the cavitation plate on the lower unit. Most boats need either a short or long shaft, although some boats require a 25″ shaft (ultra-long shaft) outboard. We recommend that you consult with your local dealer to determine the correct shaft length for your particular boat. Currently, we supply two kinds transom height for outboards (or three for some models).
The follow drawing explains the transom height in details:
Are Parsun outboards rated for salt water use and why would outboard paint come off after usage for a period?
All Parsun outboards are designed to use in both salt water and fresh water. Sometimes the outboards run in water for long time in poor environment; especially in some seas under enough sunshine, there is high environmental temperature, high salinity, flourished water plant, high salt mist in the air; and lots of sand in the water. All these factors contribute to electrochemical corrosion and physical wear for outboards. If we you not take proper anti-corrosion maintenance on the outboards, they can cause many corrosion problems and therefore reduce the life of the considerably. Parsun applies the following measures for better anti-corrosion prevention:
All Parsun outboards use special anti-corrosive grade aluminum alloy material. Through a large number of tests, it can ensure the outboard has enough strength. Special ingredient formulas of aluminum alloy are developed to avoid the inter-crystalline corrosion of the aluminum alloy.
- All non-ferrous metal spare parts apply the surface chemical treatment without chromium. It improves the ability of anti-corrosion and also avoids deleterious material leftovers.
- Use high quality and high strength stainless steel to make the key spare parts, for example: shaft, fastener and stampings.
- Adopt the proper surface paint coating to protect against corrosion. All Parsun outboards are coated by well-known brand paint from USA. In order to meet the anti-corrosion needs of different materials and solvents under different circumstances, each of the relevant parts are sprayed with paint from four to six layers.
- Adopt the self-sacrifice anode to avoid the electrochemical corrosion on the outboards. Each Parsun outboard is mounted with anodes on the engine and lower casing. The new anode meets the U.S. MIL-A-18001K standards. On the other hand, some special chemical composition is mixed with zinc to provide better anti-corrosion effect.
Because of outboards are used for different purposes and in different environment, to ensure the optimal performance and longest life, it is important to follow the instructions in the owner’s manual.
Recommend care and maintenance of outboards for corrosion prevention:
- The outboard needs to be lifted out of the water when it’s not running. Use the fresh water to clean the cooling water channel in the engine and surface of the outboards after running in the salt water.
- Clean the surface attachment of the outboard to remove, seaweed, shellfish and other foreign matters.
- If there some wear or tear on the painting when you using outboards, please have the outboard re-painted in time . Before re-painting the surface, please have the outboard treated by anti-corrosion coating first.
- Regular inspect the anode.
- Check the anode after running every 50 hours (or three months). Use the universal meter to check whether the anode has good electro conductibility, ensuring the anode has good conduction with related parts and connecting wires.
- Cleaning anode. The anode surface would produce some new chemical compound produced by chemical reaction and attach with the aquatic in the water. These factors will cause the anode not working continuously. It will cause serious consequence if the anode could not be cleaned timely. You should remove and clean the anode by the fine sandpaper and re-mounts the anode on the outboard.
- Change anode. The anode must be changed when it has excessive corrosion. Normally, we suggest the customer change the anode for every one year or one year and a half. This is to avoid paint, grease or oil attached to the anode, and to ensure the anode has the correct physical and electric connection after mounting.
Overall, anti-corrosion maintenance is very important for outboards. As long as we maintain the outboards carefully and timely, corrosion can be minimized.
Why it is necessary to pull many times to start the F4/F5 outboards?
Please note this phenomenon is caused by outboard structure design that we can’t solve at present. It is normal if you find it needs 11~15 times (sometimes more than 15 times) to start the engine. We would like to clarify the as below: When you start a new outboard, there is no fuel in the fuel pump, carburetor and fuel manifold. Therefore, it is important to add fuel (Please note that the position of carburetor is higher than that of fuel pump, the fuel needs to be pumped to the carburetor slowly by pulling the starter rope.).
Please refer to the following picture. You can manually pump fuel by using the external fuel tank instead of the internal tank to solve this problem.
Why is it sometimes difficult to start an outboard after a long period of storage?
When you experience this issues, check the owner’s manual that comes with the outboard. If after inspection, the outboards won’t start, we recommend cleaning out the carburetor because the fuel in the carburetor could deteriorate after a long period of time and produce particulate, thus affecting the starting of the outboard.
Additionally, in this case, some impurit adheres to the needle of the carburetor which can cause fuel leakage.
Always remember to use the recommended washing agent to clean the carburetor and start the outboard following these steps:
Please remember to use the special washing agent to clean the carburetor and start the outboards as the follow steps:
- Pull the starter rope slowly until the engine engages;
- Pull rapidly to crank the engine;
- Allow rope to return slowly;
- Repeat until engine starts;
- Push in the choke knob after the engine started.
Why causes some outboards to overheat?
There are several possible reasons and each may lead to this issue:
The first reason is that the cooling water passage was blocked, so you should check whether the outlet of the outboards has normal water current. We recommend you change your impeller every year at a minimum depending on the usage frequency. Another thing to remember is that even if you only use your outboard a couple of times a year, you should still have your impeller checked/replaced annually. Water pump impellers are made of rubber and will deteriorate over time even with infrequent use (commonly known as ‘dry rot’) and this can cause just as much damage to the water pump as regular wear and tear.
The second reason is that the engine oil is not enough. The last reason is that the user starts the engine out of water and then makes the water pump damaged.
Do Parsun outboards come with lower unit oil (gear oil) already filled in the factory?
Yes. But while the lower unit gear oil has already been filled at the factory, you should still check to ensure it is completely full before starting your outboard for the first time. To replace/add lower unit oil, we recommend any SAE 80 or 90 weight oil. We recommend that you consult the owner’s manual instructions on checking and changing the oil in the lower unit.
Please note: there are not gear oil added if the outboards are transported by the air, for air cargo safety reasons.
Do Parsun 4-stroke outboards come with engine oil already filled in the factory?
No. Parsun 4-stroke outboards are not filled with oil from the factory. Therefore, you must add oil to the crankcase of your 4-stroke outboard before starting it! Not doing so can severely damage your outboard, which is not covered under warranty. Please consult your owner’s manual for the proper oil type and amount to add and for the proper break-in and operating procedures.
What are the cable lengths for forward control outboards?
There are two kinds of cables for forward control outboards. One is the cable for control box; and the other is the cable for steering wheel (Please note that there are two cables for the control box, one is for throttle and the other is for gearshift). We normally provide 14’’ control box cables if you don’t have special request, but we also provide different lengths such as 12’’, 14’’, 16’’ and 20’’ if you require. For steering wheel cable, the standard size is 13” but the length can also be tailor-made upon request.
Please refer to the following drawings of cables:
Why is there a break-in period for an outboard?
The break-in period is the most critical time in the life of your Parsun outboards. Correct operation during the break-in period will prolong the life of your new outboard and will ensure optimum performance. Properly breaking-in your new outboard will ensure the initial smooth operation and lubrication of all moving parts (pistons, gears, bearings, etc).
What are the dimensions of the fuel tanks that come with our Parsun outboards?
We currently offer two sizes of external fuel tanks. One is 3.17US gallons(12L) and the net dimension is 360mm*230mm*280mm; the other is 6.34 US gallons(24L) and the net dimension is 450mm*250mm*320mm.
Are all your products with 4-stroke?
We currently offer both 2-stroke and 4-stroke outboards, ranging from 2HP to 90HP.
Do you have other types of outboard engines besides gasoline outboards?
Yes, we also have electric outboards from 5HP to 10HP, and kerosene outboards from 9.9HP to 40HP.
Do you have the forward controls with electric start ready for the market?
We have the forward controls with electric start from 9.9hp and above.
Are your outboards compliant with US EPA and Europe's CE?
Yes, Our 4-stroke outboards meet both the standards.
Is Parsun a factory or trading company?
We are the manufacturer and exporter.
How long have you been in this business?
We started the mass production of the outboard in 2006.
Can you supply spare parts?
Yes, as we are the original manufacturer.
Have you tested each piece before delivery?
Yes. At least one hour in a testing tank for each outboard. For each new models developed, over 500 hours of rigorous endurance testing is done before new models come into batch production.
What is your lead time for production?
It depends on the model. Generally speaking, two weeks in non-peak seasons; six weeks in peak seasons.