143°F 62°C Vernatherm Thermostat 0778199 394411 for Johnson Evinrude 9.9 60 90 140 200 300 HP
143°F 62°C Vernatherm Thermostat 0778199 394411 for Johnson Evinrude 9.9 60 90 140 200 300 HP
Product Overview
Vernatherm thermostat rated at 143°F (62°C) for Johnson and Evinrude two stroke outboards from 9.9 HP to 300 HP, the stat that fits the V4 and V6 loopers built between 1985 and 1995. It replaces 394411, 0394411, 778199 and 0778199, crosses to Sierra 18-1506 and GLM 13190, measures 150 mm x 180 mm x 50 mm (5.91 in x 7.09 in x 1.97 in) and weighs 20 g.
The Vernatherm is a wax pellet stat with a spring loaded bypass, not a plain car type thermostat. When it opens it also closes off the bypass, which is why a wrong or stuck stat on these motors causes overheating even with a good water pump.
The 143°F rating is the cool running one Johnson and Evinrude used on the salt water motors. Fitting a hotter stat from a different application is a common mistake and it shows up as a motor that runs fine at idle and hot at speed.
The fitment list covers a wide spread of blocks, from the 9.9 and 15 HP two cylinders up to the 300 HP V8, because the same stat body was used across the range in those years. Check the horsepower, the cylinder count and the year.
Specifications
| Specification | Detail |
|---|---|
| Condition | New / New with tags |
| Type | Thermostat, Vernatherm with bypass |
| Opening Temperature | 143°F / 62°C |
| Johnson / Evinrude Part Numbers | 394411, 0394411, 778199, 0778199 |
| Sierra Cross Reference | 18-1506 |
| GLM Cross Reference | 13190 |
| Fits | Johnson and Evinrude two stroke outboards 9.9 HP to 300 HP |
| Years Covered | 1985 to 1995 |
| Package Contents | 1 x thermostat |
| Country of Origin | Taiwan |
| Net Weight | 20 g including packaging |
| Pack Size | 150 mm x 180 mm x 50 mm |
| Pack Size In Inches | 5.91 in x 7.09 in x 1.97 in |
| Warranty | 3 year |
OEM Cross Reference
| Brand | Part Numbers |
|---|---|
| Johnson / Evinrude | 394411, 0394411, 778199, 0778199 |
| Sierra | 18-1506 |
| GLM | 13190 |
Compatible Engines
| Horsepower | Cylinders | Years |
|---|---|---|
| 9.9 HP | 2 | 1993 to 1995 |
| 15 HP | 2 | 1993 to 1995 |
| 60 HP | 3 | 1989 to 1990 |
| 65 HP | 3 | 1987 to 1990 |
| 70 HP | 3 | 1986 to 1990 |
| 120 HP | 4 | 1985 to 1990 |
| 125 HP | 4 | 1989 to 1990 |
| 140 HP | 4 | 1985 to 1990 |
| 185 HP | 6 | 1989 to 1990 |
| 200 HP | 6 | 1986 to 1990 |
| 225 HP | 6 | 1986 to 1990 |
| 275 HP | 8 | 1985 to 1988 |
| 300 HP | 8 | 1985 to 1990 |
What's Included
| Component | Detail | Qty |
|---|---|---|
| Vernatherm thermostat | 143°F / 62°C | 1 |
| Thermostat housing and gasket | Not included, reuse the original | 0 |
Signs The Thermostat Needs Replacing
| What You See | What It Means | What To Do |
|---|---|---|
| Motor overheats above idle | Stat stuck closed or bypass not closing | Fit the new stat |
| Overheat alarm after two minutes on plane | No flow past the stat | Fit the new stat |
| Motor never reaches temperature | Stat stuck open | Fit the new stat |
| Temperature climbs and drops in cycles | Wax pellet failing | Fit the new stat |
| Hot running only in cold water | Wrong temperature rating fitted | Fit the correct 143°F stat |
| Overheat after a water pump change | Old stat left in place | Fit the new stat |
Fitting Notes
| Step | Action |
|---|---|
| 1 | Check the horsepower, cylinder count and year against the table above |
| 2 | Let the motor cool and take the cowling off |
| 3 | Undo the thermostat housing and lift the cover |
| 4 | Note which way the old Vernatherm sat before removing it |
| 5 | Clean the seat and check the bypass holes are clear |
| 6 | Fit the new stat the same way round, with the pellet towards the block |
| 7 | Refit the housing with a new gasket |
| 8 | Run on muffs and check the head comes up to temperature and holds |
Condition & Warranty
| Item | Detail |
|---|---|
| Condition | New / New with tags |
| Warranty | 3 year |
| Packaging | Sealed retail packaging |
Before You Buy
- Fits Johnson and Evinrude two stroke outboards from 9.9 HP to 300 HP
- Covers model years 1985 to 1995
- Opening temperature 143°F / 62°C
- Replaces 394411, 0394411, 778199 and 0778199
- Crosses to Sierra 18-1506 and GLM 13190
- Vernatherm type with a spring loaded bypass
- Check the horsepower and year before ordering
- 30-Day Easy Returns
- Ships from our warehouse with tracking
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Before You Buy
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