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Hynautic Helm and Cylinder Alternatives

Hynautic Helm, Cylinder and Engine Control Replacement

Dometic Seastar, which acquired Hynautic has discontinued all helms, cylinders and engine controls with the Hynautic name. There is no direct replacement for the parts, but they have suggested alternatives below which can be used with modifications. Please note, these are NOT a direct fit and some mounting adjustments will be required.

We HIGHLY recommend a rebuild of your part before switching to the Seastar alternative. We are an authorized Dometic Seastar (Hynautic) service center. We offer rebuild services for most of these discontinued parts, if your part is rebuildable you can have it rebuilt by a marine tech here in San Diego.

UPDATE: Some Hynautic helms are now purchasable through us from "Hynautic" as their own brand, now manufactured in the USA. You may still transition to the Capilano alternative if you wish.

Rebuild Services:

• You can view all of our Rebuild Services Here.

Hynautic Helms	Displacement (in3/rev)	Suggested Replacement	Notes	New Helms Available for Purchase Below
H-21	2.75	HH5250	Must use (HB0573)	NEW H-21
H-22	2.00	HH5250	Must use (HB0573)	NEW H-22
H-25	2.75	HH5250	N/A	NEW H-25
H-26	2.00	HH5250	N/A	NEW H-26
H-31	2.75	HH5250	Must use (HB0573)	N/A
H-41	5.50	HH5275	Must use (HB0573)	NEW H-41
H-41-02	5.50	HH5275	N/A	N/A
H-42	4.00	HH5275	Must use (HB0573)	NEW H-42
H-42-02	4.00	HH5275	N/A	N/A
H-42-04	4.00	HH5275	Must use (HB0573)	N/A

 

Old Hynautic Helms	Displacement (in3)	Suggested Replacement	Notes
H-50	2.0	H-50 Replacement Kit	N/A
H-52	1.7	H-52 Replacement Kit	N/A

 

Hynautic Cylinders	Displacement (in3)	Suggested Replacement	Notes
K-22	13.2	HC5373-3	See note 1,2
K-31	25.5	HC5378	See note 2
K-B-5	15.9	HC5373-3	See note 3
K-9	59.8		See note 4
K-18		HC5322-3
K-19		HC5323-3
K-6 / K-6-NI	9.0	SeaStar Front Mount	See note 5
Notes: 1. Turns lock to lock will change 2. Tiller arm will requite modification to accommodate longer stroke	3. This balanced ram will physically be larger than the K-5-B, ensure adequate clearance.	4. Optimus Option	5. Cylinders volume may change, consult application guide. If using flared hose adapter HF6012

Hynautic Engine Controls:

• We recommend upgrading to KE4+ Engine Controls, an easy and direct replacement.

Technical Support:

• You can view our Technical Support page Here.