Drive unit

The Seacycle & Water Bike are equipped with unique compact, highly efficient patented drive units.

Drive unit oil

We recommend Royal Purple HPM Gear Lube SAE 80W90 High Performance Synthetic Marine Gear Lubricant or equivalent.

Each drive requires 6 ounces of oil to be filled properly. It is supplied with your new Seacycle or Water-Bike.  It is widely available at automotive suppliers or through our parts department.

You should replace the oil after each season.






Chain tension

Chain tension adjustment

Remember to check/adjust the tension as needed particularly when the chain is new.  You will know that the chain needs to be adjusted by any of three different ways:

1.Shake the drive unit sideways; if you hear the chain hitting the side walls it is too loose.

2.Hold the prop still while gently turning the pedals; should not have more than about an inch of play.

3.Chain slips or derails unexpectedly  

New drive units or chains should have the chain tensioned (it is already adjusted at the factory):

1.When the drive unit is new from the factory, before the first use, perform the above tests 1 and 2 to see if the chain is loose. If so, adjust the chain tension before the first use.

· NOTE: don’t forget to put the oil in the drive unit

2.After the first 2-3 hours of use, check the chain tension. Adjust the chain only if it is required.

3.After the first day of use, check the chain tension and adjust if required.

4.After the first week of use, especially for rental operation, check the chain tension and adjust if required.

5.Chain should be checked at least 1 time per month after that for home use, and a minimum of weekly in resort/commercial use.

6.This is also a good time to check drive shaft for tangled debris to avoid damage to O-Ring seal that keeps it water tight.  Marine grade silicone sealant can be applied to keep water out as needed.

Chain tightening & stop bracket adjustment procedure:

Chain tension is accomplished by moving the **main crank shaft spindle up or down.  

Step 1 - Loosen the spindle hub washers-nut:

Loosen BOTH sides of the ***spindle hub washers on **main crank shaft, using the large wrench that came with your parts. To loosen them, do 2 to 3 complete turns.  If you loosen it more than that, you will begin to disassemble parts.  

Step 2 – Tighten the chain with the screws on top:

Once both spindle hub washers are loosened the main crank shaft assembly will, with slight pressure, move up & down in slots in the sides of the *drive unit housing.  To pull the main crank assembly up:  tighten the two Phillips head screws in the top of *drive unit housing cap until tight, being careful to not over tighten.

If you over tighten the screws, the chain will be to tight and the pedals will be difficult to turn. So you just have to tight the screws a little bit in order to feel that you have removed the loose in the chain, not more. Check immediately to see if the chain touches the side walls when you shake the drive unit sideways. If it doesn’t than the chain is perfectly tighten.

Step 3 – Re-tighten the spindle hub washers-nut:

Re-tighten both spindle hub washers with the large wrench firmly.

Step 4 – Optional step to adjust the drive unit vertically (not related to chain tension):

If the drive unit is not vertical, but tilted forward or backward, check the vertical stop bracket & adjust the set screws as needed to keep the unit balanced vertically. To adjust this bracket, loosen the 4 bolts two or three turns; slide the bracket up or down as needed & re-tighten.

Chain replacement
1.Loosen the ***spindle hub washers
2.Loosen/remove the Phillips head screws on drive unit housing cover to disengage the chain tensioner & then remove the drive unit cover. 
a.You will be breaking the silicone seal to remove it while being careful to not damage the rubber gasket. 

3.Open the master link on the chain; both on the old chain & on the new chain to install it.  

4.To correctly install the chain, start with the drive unit (with prop facing towards yourself) just like it is on the boat.  Drop the chain down to the lower gear & with the help of another person, slowly turn the pedal until the chain turns onto the gear.  
a.IMPORTANT: The chain on the right side of the gear should be closest to you for correct installation to propel forward.  Your drive unit will propel in reverse if this is done on the other side.

5.Once the chain is around the gear, turn drive unit upside down to allow chain to drop out of top as you slowly turn the pedals to advance it.  

6.Re-attach the master link & replace drive unit cover.  
a.Replace rubber gasket & apply marine grade silicone to seal the cover. 

7.Adjust the tension of the chain by slowly tightening the screws on the top of the drive unit cover and then re-tightening the spindle hub washers (see chain tension adjustment above).


*DRIVE UNIT HOUSING:  Exterior component that holds the drive unit components

**MAIN CRANK SHAFT: Spindle that pierces the drive unit housing to which the pedals attach.

***SPINDLE HUB WASHER:  Black round discs about 2" in diameter with a flat side; mounted to each side of the drive housing through which the Main Crank Shaft protrudes.  The drive bushings slip into the U shaped cutouts in the main yoke that hold the drive unit in place.

****VERTICAL STOP BRACKET:  On the back side of the upper end of the drive unit housing