150 Faststrike Johnson

C

cub48

Seaman
Joined
Dec 17, 2009
Messages
54
I have a 1998 150 Faststrike It is the best starting engine i have ever owned. Push the key in and spin it over and 2 times it starts. It idles a little rough but does not die. It smells it is running a little rich. Smokes when you start and at idle not excessive. But at 1200 rpm it runs real rough.Say you are moving from one spot to another and just fast idle to get there. It jerks and feels like it is missing.It will run down river 35mph and faster smooth as silk. I have put seafoam and stablizer in run gas without elthol. used 92 oct. Changed plugs this spring. Supposed to have had the carbs sink and adjusted I think all they did was idled it up. Checked compression when i bough it was 110 on all cylinders. I am an auto tech and a miss tuned engine bugs me. I am not up on 2 strokes yet and I have already spent money and have the same problem. Thanks Cub48
 
dish

dish

Petty Officer 2nd Class
Joined
Aug 22, 2008
Messages
151
Re: 150 Faststrike Johnson

Have you checked to see if your cam follower roller is still intact.If thats missing it can put the timing out.
 
J

jonesg

Admiral
Joined
Feb 22, 2008
Messages
7,174
Re: 150 Faststrike Johnson

Run it til it is rough, whatever rpm that is, then hit the choke (push the ignition key in) if it picks up the carbs are clogged.
If it bogs down its not the carbs.
Sounds like carbs, maybe intermediate jets.
If you do them, run wire thru the jets and orifices in the throat.
 
reeldutch

reeldutch

Lieutenant
Joined
Feb 2, 2004
Messages
1,340
Re: 150 Faststrike Johnson

i bet you it is not comming out of quickstart.
does it clunk when you shift it?
what rpm does it idle at in gear?
 
B

boobie

Supreme Mariner
Joined
Nov 5, 2009
Messages
20,826
Re: 150 Faststrike Johnson

Start it up and disconnect the white/black temp sensor wire on the port side. Then ground it out to the block. If your idle changes it was stuck in QS. This can be caused by mtr temp, bad temp sensor or power pack.
 
C

cub48

Seaman
Joined
Dec 17, 2009
Messages
54
Re: 150 Faststrike Johnson

It Idles at around 800 rpm it apears to be running rich. Does these carbs have adj air screws Thanks Cub48
 
8

8up

Petty Officer 3rd Class
Joined
Nov 2, 2003
Messages
98
Re: 150 Faststrike Johnson

I suggest you pull your thermostats, you may have one stuck open and not letting the motor come up to operating temp. Easy enough to check.
 
J

jonesg

Admiral
Joined
Feb 22, 2008
Messages
7,174
Re: 150 Faststrike Johnson

8up said:
I suggest you pull your thermostats, you may have one stuck open and not letting the motor come up to operating temp. Easy enough to check.
Click to expand...

Its easy as putting your hand on the cyl heads.

Time for troubleshooting.
Do a spark test , set gap to 7/16th inch.
 
C

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
27,158
Re: 150 Faststrike Johnson

Cub, You might check the idle mixture adjustment needles. On my '98 Johnny 150HPV6, the idle needles are hollow and had some dirt in the ldle passages. I was able to blast each needle with some Seafoam Deep Creep. I let it sit a day or so, and then ran the motor. It now idles quite a bit better than before the treatment.
Of course the balance of the carbs needs to be clean as well, for this to work.
 
C

cub48

Seaman
Joined
Dec 17, 2009
Messages
54
Re: 150 Faststrike Johnson

Carried the boat out Saturday the rough idle comes in at about 1000 rpm leaves at about 1200 rpm. chocked it while it was doing and the motor bogged down. It is not running lean. It is rich. Talked to a shop he said it may be trash under a needle or a cracked ventura. Cub48
 
S

seahorse5

Rear Admiral
Joined
Jan 24, 2002
Messages
4,698
Re: 150 Faststrike Johnson

Chances are the carb roller is broken and/or the spark-timing synchronization is not adjusted correctly.

Look at the roller, it should be about 1/4-3/8" in diameter. If it looks about 1/8" diameter, then the outer covering is broken off.

They are only about $8 at a dealer. Follow the service manual procedure for synchronizing the linkage.
 
J

jonesg

Admiral
Joined
Feb 22, 2008
Messages
7,174
Re: 150 Faststrike Johnson

cub48 said:
Carried the boat out Saturday the rough idle comes in at about 1000 rpm leaves at about 1200 rpm. chocked it while it was doing and the motor bogged down. It is not running lean. It is rich. Talked to a shop he said it may be trash under a needle or a cracked ventura. Cub48
Click to expand...


Its supposed to run rich when you hit the choke .

Now check the choke solenoid, look for leaking around the cap near the red lever. Its a common failure that will flood the manifold.
It can be rebuilt for under $15.

It could be as the others suggest, link and sync is slightly off, it has to be set up correct for transition to work smooth.
I would rebuild all the carbs if the choke is not weeping fuel and check the sync.
 
C

cub48

Seaman
Joined
Dec 17, 2009
Messages
54
Re: 150 Faststrike Johnson

I know it is supposed to run rich when you hit the choke. But if you had a carb running lean it should smooth out. It just ran richer.When I get time I am going to remove the air box start the engine with the hose on it and watch the carbs check the roller and see if i see any leaks. may pull plugs out and look at them. See if one is fouling more than the other. Cub48
 
J

jonesg

Admiral
Joined
Feb 22, 2008
Messages
7,174
Re: 150 Faststrike Johnson

cub48 said:
I know it is supposed to run rich when you hit the choke. But if you had a carb running lean it should smooth out. It just ran richer.When I get time I am going to remove the air box start the engine with the hose on it and watch the carbs check the roller and see if i see any leaks. may pull plugs out and look at them. See if one is fouling more than the other. Cub48
Click to expand...

Sounds good, you can try choking each carb in turns by putting 2 fingers across the throat, listen to how it runs, it should slowly go rich from the choking.

A good way to inspect plugs is install new ones, run it up to WOT then turn the ignition off, remove and inspect plugs.
 
C

cub48

Seaman
Joined
Dec 17, 2009
Messages
54
Re: 150 Faststrike Johnson

Hi Guys I pulled the cover on my engine today. I checked the roller and it is broken I will check the dealer and see if they have one. Maybe this will fix my problem.Thanks for all your help Cub48
 
J

jonesg

Admiral
Joined
Feb 22, 2008
Messages
7,174
Re: 150 Faststrike Johnson

yES that will fix the problem, its a wear item, designed to wear out and be replaced instead of ruining the cam itself.
 
You must log in or register to reply here.
Top