1986 4 HP Johnson head air cooled?

Hi All
I have a 1986 4 HP johnson who's head seems to be getting HOT. It is melting a 163 stick no problem. The motor is pumping tons of water. I don't see a place where a thermostat would be on this little booger. Is the HEAD air cooled? I don't see a thermostat on the parts diagram either.....

Re: 1986 4 HP Johnson head air cooled?

no and don't run it till you find out why. brp is down so i can't look at diagram.

Re: 1986 4 HP Johnson head air cooled?

It's the deluxe model I believe........ model number is E4RDHCDE
The rest of the block doesn't melt the stick....dang I hate to have to pull the head.

Re: 1986 4 HP Johnson head air cooled?

I was able to get on BRP, link to exploded view is below

Re: 1986 4 HP Johnson head air cooled?

1 0389682
Add to pick list CYLINDER & C'CASE ASSY. 1 7
2 0314951
Add to pick list SCREW, Cyl. to c'case 8 4
3 0304067
Add to pick list PLUG, Large 1 5
4 0307588
Add to pick list PLUG, Small 1 5
5 0322831
Add to pick list SCREW, Center 2 6
6 0323522
Add to pick list WATER DEFLECTOR 1 4
7 0328158
Add to pick list TUBE, Crankcase drain 1 6
8 0300402
Add to pick list TAPER PIN 1 5
9 0328159
Add to pick list TUBE, Crankcase drain 1 6
10 0314951
Add to pick list SCREW, Mfld. to c'case 4 4
11 0395711
Add to pick list CYLINDER HEAD 1 7
12 0332010
Add to pick list GASKET, Cylinder head 1 2
13 0307471
Add to pick list SCREW, Cylinder head & fuel tank 4 4 Models with Integral Fuel Tank Only
14 0320107
Add to pick list TIE STRAP, Pulse hose 2 1 Models with Integral Fuel Tank Only
15 0324570
Add to pick list MOUNTING BRACKET, Fuel tank, upper 1 7 Models with Integral Fuel Tank Only
16 0302750
Add to pick list SCREW, Cover plate 8 6
17 0386941
Add to pick list SPARK PLUG, Champion L77J4 2 1
17 0387633
Add to pick list SPARK PLUG, Champion QL77J4 2 7
18 0323263
Add to pick list PLATE, Exhaust cover 1 4
19 0323445
Add to pick list GASKET, Cover plate 1 3
20 0324571
Add to pick list MOUNTING BRACKET, Fuel tank, lower 1 7 Models with Integral Fuel Tank Only
21 0326544
Add to pick list NIPPLE, Pulse head to cylinder 1 4 Models with Integral Fuel Tank Only
22 0325881
Add to pick list PULSE HOSE 1 7 Models with Integral Fuel Tank Only
23 0323446
Add to pick list GASKET, Plate to c'case 1 4
24 0314951
Add to pick list SCREW, Cylinder head 0 4
25 0302750
Add to pick list SCREW, Ground 1 6
26 0388941
Add to pick list MANIFOLD, Intake 1 5
27 0323444
Add to pick list GASKET, Manifold 1 4
0388653 0388653
Add to pick list LEAF PLATE ASSY. 1 7 Not Shown
28 0303764
Add to pick list SCREW, Leaf to plate 4 5
29 0314915
Add to pick list LEAF VALVE 2 4
30 0323485
Add to pick list PLATE, Leaf back-up 2 5
31 0385111
Add to pick list CHECK VALVE 1 4
32 0322927
Add to pick list LEAF PLATE 1 5
33 0305344
Add to pick list SCREEN 1 4
34 0330812
Add to pick list SHIM, Leaf plate 2 5
35 0303701
Add to pick list LOCKWASHER, Ground lead 1 4
36 0389554
Add to pick list POWERHEAD GASKET SET 1 7

Re: 1986 4 HP Johnson head air cooled?

Hmmmmmmmm......
Maybe I have the wrong plugs in it?
This diagram calls for the L77JC4

My Champion books stated it took the L86C
and my NGK book stated BR6HS
I put a couple of B6HS plugs in it

Re: 1986 4 HP Johnson head air cooled?

THe other plugs didn't cure it,lol.

Re: 1986 4 HP Johnson head air cooled?

Ok, it's AM and I'm looking at it with a new set of eyes and I think it's overheating.

I took a picture of the Sierra gasket, it looks a lot different than the OEM.

Looks like it's going to have to have an OEM head job?

Re: 1986 4 HP Johnson head air cooled?

Dang! I hate being such a curious monkey!
I went ahead and pulled the head and I found a picture of the OEM head gasket instead of the illustration. The OEM head gasket looks identical to the Sierra one. I think a couple of extra holes punched in it might help?
Does anyone know if the water is supposed from bottom up or top down on these?

Re: 1986 4 HP Johnson head air cooled?

Dang is right! That's exactly the motor I've been looking for. If ya get tired of it, let me know...ha. In the meanwhile, I'll keep looking....ahem....