4HP Johnson Seahorse quit, now wont start PLS HELP!

[Truckster]

Re: 4HP Johnson Seahorse quit, now wont start PLS HELP!

I really truly appreciate everyone's help and suggestions,.Thanks fellas!!!
This is a great site so glad i came across it while googling my motor troubles.Ya'll be the first to know when i get it going soon and I will definaltly be able to help others who may have same issues too once i figure out mine.
CHEERS!!!

 

[raczekp1]

Re: 4HP Johnson Seahorse quit, now wont start PLS HELP!

hi.
teke the bolte and conect this botle with hose.the other end of hose conect with carb(avoid the fuel pump)fill the boltle with fuel. the botle should be with hole that is some kind of vent hole.
hoke the bolte higher hthan engin is standing, fuel should float to carb by gravity help.
wait that gravity will push fuel to carb, tray to start engin, with chike on.engin will suck the fuel with gravity help.
if it start that you will know if fuel pump is not working.
try to measure compresion in both cylinders usuing compresion tester from autostore.
if compresion is low, check screws mounting fuel pump.under fuel pump is gasket, if is not fiting tight your engin will lose presure.
tighten this screws, but not hard.measure compresion.
if not helps, there is propablu seals lower and top is not holding preasure to make enaugh vacum to soak fuel

 

[Truckster]

Re: 4HP Johnson Seahorse quit, now wont start PLS HELP!

Thanks raczek!! Will try it!! your spelling was a bit different but I think I got the idea.
Heading out now for more motor fun

 

[outlaw241]

Re: 4HP Johnson Seahorse quit, now wont start PLS HELP!

with the carb in your hand right side up blow in the fuel inlet with your mouth you should hear air passing through [needle & seat should be open], now turn carb upside down an blow again, no air should be passing through [needle & seat should be closed]. if when you squeeze the primer ball an you can see the carb is getting flooded it is definitely a needle & seat issue

 

[Truckster]

Re: 4HP Johnson Seahorse quit, now wont start PLS HELP!

with the carb in your hand right side up blow in the fuel inlet with your mouth you should hear air passing through [needle & seat should be open], now turn carb upside down an blow again, no air should be passing through [needle & seat should be closed]. if when you squeeze the primer ball an you can see the carb is getting flooded it is definitely a needle & seat issue

carb is all good.
I just did a compression test and the top plug hole was reading a little over 30psi and the bottom plug was right on 30psi hmmmmm anybody think it maybe just the head gaskit needs to be replaced???Or rings too? Personally I'm hoping its just head gaskit!

 

[Truckster]

Re: 4HP Johnson Seahorse quit, now wont start PLS HELP!

sorry I didnt do test right the first time,didnt pull cord enough.My bad!
So I just did it again and pulled it like I was trying to start maybe 8-10 pulls and the highest reading I got in both plug holes was close to 50psi.
Is that bad? Should I try getting a new head gasket first then do another test?

 

[OptsyEagle]

Re: 4HP Johnson Seahorse quit, now wont start PLS HELP!

Did you have both spark plugs out when you did each cylinder? Your compression numbers are very low but its pecular that they are both even. I would think it unlikely that even a blown head gasket would lower the compression "equally" on both cylinders. I suspect that the test may have not been done right or the tester you are using is not that good.

Others may have some thoughts.

 

[14ftgrumman]

Re: 4HP Johnson Seahorse quit, now wont start PLS HELP!

When you get it running, follow the "decarb" process in the "top secret files. This might bring up your compression numbers. A god dose of Sea Foam never hurt anything.

 

[Truckster]

Re: 4HP Johnson Seahorse quit, now wont start PLS HELP!

Did you have both spark plugs out when you did each cylinder? Your compression numbers are very low but its pecular that they are both even. I would think it unlikely that even a blown head gasket would lower the compression "equally" on both cylinders. I suspect that the test may have not been done right or the tester you are using is not that good.

Others may have some thoughts.

I did one plug out at a time,the proper way.There is only one piston in the 78 Johnson 4hp.I seen teardown diagrams at usboatsupply.com.So looks like just one cylender but for some reason 2 plugs.The top plug did have a little tiny bit more psi but not much.Tester I brand new,just bought it and its a good one I didnt really feel like paying for but atleast I will always have one handy.I tested both plug holes seperate with one sparkplug in one hole and tester in the other,pulled cord 8-10 maybe more time like i was attempting to start it,then checkeck guage.At around the 6-7th pull i noticed the guage stopped going up.Test complete!
Should I buy a new head gasket and retest see if that gives me a higher reading?They are not expencive so cant hurt to try.
Any more ideas???

 

[bktheking]

Re: 4HP Johnson Seahorse quit, now wont start PLS HELP!

Sorry to tell you, it's got 2, 2 plugs and 2 cylinders and 2 pistons. The diagram you looked at showed 1 piston, if you look at quantity it's 2. Pull both plugs and retest, post your readings.

 

[Truckster]

Re: 4HP Johnson Seahorse quit, now wont start PLS HELP!

When you get it running, follow the "decarb" process in the "top secret files. This might bring up your compression numbers. A god dose of Sea Foam never hurt anything.

Well that sounds nice if I can ever get it to run
By now I pretty much know "top secret files" off by heart lol this motor is killing me!!! lol I will prevail!!!!!
even if it almost kills me.

 

[Truckster]

Re: 4HP Johnson Seahorse quit, now wont start PLS HELP!

Sorry to tell you, it's got 2, 2 plugs and 2 cylinders and 2 pistons. The diagram you looked at showed 1 piston, if you look at quantity it's 2. Pull both plugs and retest, post your readings.

ok just did it again, Here is what my guage looks like-30 | | 60psi the top plug hole stopped at the last mark just before 60psi and the bottom plug stopped right in the middle between 30 and 60.Hope this gives anyone an idea of what I'm seeing on my guage and what could this meen as for getting my motor to start again?

 

[bktheking]

Re: 4HP Johnson Seahorse quit, now wont start PLS HELP!

Check your head bolts, try tightening them, you'll know if they are loose when you go to turn them. If they are loose on the side with the lower piston reading, restest your compression once retightened. That is a "free" method to try and troubleshoot.

 

[Truckster]

Re: 4HP Johnson Seahorse quit, now wont start PLS HELP!

Check your head bolts, try tightening them, you'll know if they are loose when you go to turn them. If they are loose on the side with the lower piston reading, restest your compression once retightened. That is a "free" method to try and troubleshoot.

Thanks! I will have another go at it in the morning and try that but what if it doesn't go up much? Isn't that psi range im getting too low and what should my compression be in order to run or atleast start half decent?

 

[bktheking]

Re: 4HP Johnson Seahorse quit, now wont start PLS HELP!

Not really, 45psi is pretty low, 60 on both would be "ok" compression and would run. If that doesn't work it's time to pull the head off and inspect the gasket, head and cylinder walls for scoring. Another method telling if you have a ring issue is to pour some 2 stroke oil into the low cylinder (with the pistons facing up) and restesting, if compression increases chances are it's a ring issue.

 

[samo_ott]

Re: 4HP Johnson Seahorse quit, now wont start PLS HELP!

30 and 60#'s? That's way too low. You'll have to pull the head off to see what's happening inside. And hopefully it's only the gasket. Did you overheat it? That could have been the original problem. Have you ever checked or changed the water pump impeller?

 

[Truckster]

Re: 4HP Johnson Seahorse quit, now wont start PLS HELP!

30 and 60#'s? That's way too low. You'll have to pull the head off to see what's happening inside. And hopefully it's only the gasket. Did you overheat it? That could have been the original problem. Have you ever checked or changed the water pump impeller?

Im not too sure if it overheated? Was no smoke or anything.I have never checked or changed the water pump impeller and that was another thing I was wondering about.When I was turning it over ther was water misting out of the holes,not sure if that meens its actually working or not though.What do I check for?What does a bad waterpump look like?.
Its aslo been getting lots of blackish brown oil around the bottom of the shaft though while attempting to start the day it failed and while in the bucket.Its the weedless drive version and if exhaust cover leaks of takes on water can that damage anything or cause my problem?I noticed a good ding on it.

 

[Truckster]

Re: 4HP Johnson Seahorse quit, now wont start PLS HELP!

Im not too sure if it overheated? Was no smoke or anything.I have never checked or changed the water pump impeller and that was another thing I was wondering about.When I was turning it over ther was water misting out of the holes,not sure if that meens its actually working or not though.What do I check for?What does a bad waterpump look like?.
Its aslo been getting lots of blackish brown oil around the bottom of the shaft though while attempting to start the day it failed and while in the bucket.Its the weedless drive version and if exhaust cover leaks of takes on water can that damage anything or cause my problem?I noticed a good ding on it.

If ya look up parts www.usboatsupply.com (johnson-4hp-1978-4W78E-gearcase/weedless drive) I have a ding on the part#15 COVER, Exhaust.its sitting a little crooked like it bent from rock or something.Could water possibly get in that and cause problems?

 

[raczekp1]

Re: 4HP Johnson Seahorse quit, now wont start PLS HELP!

hi.
sorry for my speling.
did you check the gasket under fuelpump?this gasket can couse compresion leak.
change your head gasket and when you take of the head cover look into the cylinder to see cylinder wals
if you did the overheating you will have burned paint in the powerhad, especialy in the conection between powerhad and midsection.
also its good to change lower seal which is underpowerhad.so yo should unscrew 6 bolts conecting powerhad with midsection

 

[Truckster]

Re: 4HP Johnson Seahorse quit, now wont start PLS HELP!

Well I attempted to check the head gasket this morning and the bolts were super corroded and one even snapped off and another just wont budge.I threw down my sword and took it in to the local outboard repair shop they are going to try and get that last 2 bolts off and try put heat to it.The one that snapped didnt bend or anything so hoping heat will do the trick and they are going to check the cylender while checking head gasket.They said the head gaskets can blow in the middle between the 2 cylenders so hopefully them bolts can be taken out because if not than its junk they said.If all bolts come out im hoping its just the head gasket replaced and some new bolts for the head.If all goes the right way I might just get a new water pump just to be safe.Thats if I don't have to junk it.