1990 88 hp johnson spl missfire

[3dhunt]

Have an issue with my 88 spl outboard and can't find any one else who shares the problem. The engine runs great off the trailer. Starts great, idles and runs across the lake right just as it should. We drift fish so once we find our area, the engine is shut off for maybe up to 30-45 min. The problem is when you try to restart. The engine will only restart by lifting the fast idle lever wide open. Once the engine starts and cleans out, it wont idle but you can get across the lake. It will continue to do this the rest of the day. Take the boat home, let it set a week, and it does the same thing next week. After this week I pulled the plugs (new ngk's) and what I think is cyl #4 (port side lower) is fouled. Is there anything different on cyl. 4 that would cause this. thanks for any help!!!!! 3d

 

[Daviet]

Re: 1990 88 hp johnson spl missfire

Does your fuel pump mount to the block or is it remote mounted?
Does the pulse system run off of #4 cylinder, does it have fuel in it.
You should be using champion plugs.

 

[boobie]

Re: 1990 88 hp johnson spl missfire

Get yourself an open air gap spark tester, set it to 7/16 " and take it with you and check the spark when the prob occurs. This will eliminate the ign system if there's a prob or not with it. Always trouble shoot one step at a time.

 

[3dhunt]

Re: 1990 88 hp johnson spl missfire

Does your fuel pump mount to the block or is it remote mounted?
Does the pulse system run off of #4 cylinder, does it have fuel in it.
You should be using champion plugs.

pump bolts to the block portside next to lower carb top mounting bolt. help me understand pulse system question. not sure what a pulse system is. sorry i'm an auto mech. thanks

 

[boobie]

Re: 1990 88 hp johnson spl missfire

The fuel pump runs off of crankcase pulses. Take the fuel pump off and put some 10/24 nuts on the mounting screws and tighten. Then pump your primer bulb to see if you get any fuel out of the pulse hole. If you do, you have a bad fuel pump diaphram leaking into # 4 cyl.

 

[3dhunt]

Re: 1990 88 hp johnson spl missfire

The fuel pump runs off of crankcase pulses. Take the fuel pump off and put some 10/24 nuts on the mounting screws and tighten. Then pump your primer bulb to see if you get any fuel out of the pulse hole. If you do, you have a bad fuel pump diaphram leaking into # 4 cyl.

fuel pump was rebuilt in april but i checked like you said and it shows no fuel leaking through.

 

[boobie]

Re: 1990 88 hp johnson spl missfire

What's the compression like ??

 

[3dhunt]

Re: 1990 88 hp johnson spl missfire

all 4 - 115 to 118

 

[boobie]

Re: 1990 88 hp johnson spl missfire

Did you ever check the spark with the air gap tester ??

 

[3dhunt]

Re: 1990 88 hp johnson spl missfire

i havent been back to the lake yet to test spark, what about the primer solenoid, i know the lever is pointed right but is there some way it can malfunction and allow fuel to enter the cyls. after initial startup. I know it works some because I use it to start cold.