I have a lethargic Johnson 150

[cmacky]

I have a 1985 vro 150 gt johnson outboard on a 18ft. laser boat. I am running a 24 raker sst prop. motor has been rebuilt, heads done, broke in and new plugs. The motor is very sluggish, very slow to plane out and I can only get around 4000 rpm out of it. Also, sometimes when running it will just fall flat on its face, like all fuel or fire has been taken away. it will start right back up but will do the same thing again after a short run of a couple of miles or so. it is not getting hot or anything, and everyone has a different opinion about it. If anyone could give me advice I would appreciate it..... I will add that as of right now I have not started checking anything other than the obvious. I have been told that a bad stator can do this. does this sound right? I am not very good on these boat motors.

 

[Dhadley]

Re: I have a lethargic Johnson 150

Did it run this way before the rebuild?<br /><br />Is it running on all 6?<br /><br />Is the linkage going to full advance?<br /><br />Whats the timing set at?

 

[cmacky]

Re: I have a lethargic Johnson 150

I did not own it before rebuild, so I dont know how it ran. It is firing on all 6, and it is getting WOT. I am not sure about the timing, I just had the heads worked on recently and the timing is supposed to be correct. I have to trim the motor to get it to idle. It does not seem to have a miss that I can tell. It just shuts down without warning. Almost like hitting a kill switch.

 

[Dhadley]

Re: I have a lethargic Johnson 150

Originally posted by cmacky:<br /> I just had the heads worked on recently and the timing is supposed to be correct.

What did they do to the heads?<br /><br />Something is pretty far off because you are about 2000 rpm short of where you need to be. I would take it back to whoever built it and ask them to run it in the water. I'd also ask them what they set the timing at.

 

[cmacky]

Re: I have a lethargic Johnson 150

It had a blown head gasket. So in fixing that he recommended that I have the heads shaved. I agree something is off, I will have him check the timing. What would be causing the shut down?

 

[Dhadley]

Re: I have a lethargic Johnson 150

Find out how much he "shaved". Very important.<br /><br />With a top rpm of only 4000 we would expect the response to be sluggish. I'm almost leaning toward thinking something electrical at this point. I do believe all this is tied together. If there is any type warranty I would not run it until you take it to him to be fixed. It also is concerning as to why it blew a head gasket. That usually happens after a sever overheat. Thats a strange situation on a fresh rebuild. It should have a fresh water pump assembly as part of the rebuild. New deflectors and thermoststs too. <br /><br />Good luck!

 

[cmacky]

Re: I have a lethargic Johnson 150

I am trying to learn more about outboards as I have time. The last boat I had never tore up so it didn't help me learn much about working on them. Now this motor I have has stayed messed up. It is very frustrating cause I dont know what to look for on troubleshooting. Thanks for trying to help....

 

[Dhadley]

Re: I have a lethargic Johnson 150

When you said it is getting WOT as far as the linkage is concerned, are you refering to the throttle handle or have you checked the timer base travel to make sure its up aginst the stop and the carbs are completely opening?

 

[cmacky]

Re: I have a lethargic Johnson 150

the heads were shaved 30. Also I installed a new starter battery and it has already went dead after only 2 times out. I wish I had my 70 evinrude on my little runabout back...This sucker is becoming a money pit

 

[Dhadley]

Re: I have a lethargic Johnson 150

Depending on which heads you have .030 is way too much. Especially if its the correct 150 GT heads. <br /><br />If the battery is going dead that may indicate a stator problem. Look up under the flywheel. There are windings that make up the stator. There will be some larger windings. Is there a goo-like substance leaking from them?<br /><br />You said the motor gets to 4000 rpm so we are assuming the tach still works, correct? If not there may be a reg/rec problem.

 

[cmacky]

Re: I have a lethargic Johnson 150

yes, the tach does work. I will check the stator as soon as I can. He told me what was done to my heads was not a lot. I was told he was just doing enough to make them true, so maybe I have my numbers crossed on how much he shaved off. I am not sure what a stator looks like, does it look like copper or is it coated wire? I am not very good at this so please have patience with me...lol

 

[Dhadley]

Re: I have a lethargic Johnson 150

Good. Since the tach works the rectifier/regulator is most likely OK. <br /><br />The stator supplies initial voltage to the ignition system and acts as the alternator. Yes, it will be the wire windings right under the flywheel. You will be able to see them without removing anything other than the hood.

 

[cmacky]

Re: I have a lethargic Johnson 150

Thanks for the info. I will check the stator as soon as I get home. I will also check the throttle linkage to make sure I am getting WOT.If not that could solve my rpm problem, but I still would have the problem of shutting down with no warning. I will let you know what I find out. Thanks for the help.

 

[Cricket Too]

Re: I have a lethargic Johnson 150

Once you get the cutting out problem solved, you may want to try a different prop on that motor, could be the reason you're only getting 4000 at WOT and sluggish out of the hole. I had a 150 on a 19' Mako and used a 19" pitch on that and had really good hole shot and about 5700 WOT. Good luck.

 

[OBJ]

Re: I have a lethargic Johnson 150

Cmacky...you posted earlier that you have to "trim" the engine to get it to idle. Please elaborate a little on this. May point to something.<br /><br />Thanks.

 

[bonitoman]

Re: I have a lethargic Johnson 150

Change the pitch on the prop to 17 or 19. 24 will lug the engine and burn it up and then you will be looking at a rebuild. MMPECK said 19 and he is correct. I prefer a 17 myself.

 

[cmacky]

Re: I have a lethargic Johnson 150

As far as trimming the motor, I have to trim it up to get it to Idle. If not it loads up and you can see a lot of unburnt fuel in the water. I agree with you guys thinking the prop is too big but some guys have told me to stick with it. I know johnson recommends a 19 so I was thinking a 24 was way to much. There is a boat shop local here and they tell me they will trade outright with me so I think I will. Thanks for your input fellas, I dont know a whole lot about outboards but I am learning more after getting on this site. I will keep ya posted. Think I will switch props today!

 

[Dhadley]

Re: I have a lethargic Johnson 150

If you have the 18' Laser bass boat with the pad and step bottom the prop may not be that far off. We need to get the motor running correctly first. The Lasers I've seen sit down pretty far in the back so at idle you either have to lift the jackplate or tilt the motor up slightly to relieve the backpressure.

 

[walleyehed]

Re: I have a lethargic Johnson 150

I'm with Dhadley...hang on to that prop, I think you've got some other issue.<br />With a proper set-up, and correctly running engine, you would be over-reving with a 19".<br />I'm wondering if the engine got hot and galded the rings in the piston(s).<br />Can you call the person that O/H'd your engine and clarify how much was removed from the heads???<br />Hang tight, that should be a good engine for ya, we just gotta figure out where the gremlins are..

 

[cmacky]

Re: I have a lethargic Johnson 150

I just called the guy who overhauled my motor, heads had .015 took off. all pistons rings and waterpump are completely new. Carbs rebuilt also, new fuel pump and new gas tank and lines. The boat does set down in the back quite a bit, so I see what your saying about the trim. Mechanics are expensive I am finding out, so I am trying to fix this on my own. engine has about 12 hours on it after rebuild.