25HP johnson

FTB530 · Mar 28, 2012

Im new to this forum and i hope im not repeating a question , hope some one can help or give me an idea what to do next.

The engine started running bad and smoking,(lent it to a buddy) and this is how i got it back,i took the spark plugs out and water was in the cylinders,so i changed the head gasket and thermostat and new plugs and fresh gas,it still runs about the same and still smoke when put in gear and throttled up. Can any one give me an idea what i should check next. Thanks for any help.

FTB530 · Mar 28, 2012

Re: 25HP johnson

I for got to mention and after seeing another 25 hp in a video on this forum,where the two exhaust ports are it was shooting water out of them after i changed the head gasket. any info will help thanks

Lone Duck · Mar 28, 2012

Re: 25HP johnson

FTB530 said:
I for got to mention and after seeing another 25 hp in a video on this forum,where the two exhaust ports are it was shooting water out of them after i changed the head gasket. any info will help thanks

check to see if head gasket has a good seal, and if it is on the wrong way..

FTB530 · Mar 29, 2012

Re: 25HP johnson

Lone Duck said:
check to see if head gasket has a good seal, and if it is on the wrong way..

I dont know how i can check to see if it has a good seal, but i put a new head gasket on and it was on right and torqued to specs,thanks

Johny25 · Mar 29, 2012

Re: 25HP johnson

Are you still getting water in the crank case? And did you resurface the head and block before installing the new head gasket?

F_R · Mar 29, 2012

Re: 25HP johnson

Excess "smoking" is a by product of running poorly. In other words, it is a symptom, not the disease itself. Having said that, it is SUPPOSED to smoke some. It's just a matter of what is normal.

Water in the cylinders is a serious problem, and will destroy the motor. If it still is getting water in there with a new head gasket, the next most likely entry route is the exhaust covers on the side of the powerhead.

What year motor are we discussing, anyway?

FTB530 · Mar 29, 2012

Re: 25HP johnson

The motor is a 1985,i did not resurface the head or block,i didnt want to spend a lot of money on the engine,but i guess at this point i may have to or buy new.

jasper60103 · Mar 29, 2012

Re: 25HP johnson

FTB530 said:
The motor is a 1985,i did not resurface the head or block,i didnt want to spend a lot of money on the engine,but i guess at this point i may have to or buy new.

Well, let's not assume the worst just yet. As Johny indicated, resurfacing the cylinder head is usually done if you change the head gasket, but it still may be OK. I would do a compression test to confirm the head gasket is not leaking. You should see 100+ psi and fairly equal on both cylinders. If you don't have a compression tester, you can borrow one for free at Autozone or Oreilly's auto part stores.
And if you're still getting water in the cylinders, I would follow F_R's advice.
I never changed an exhaust cover gasket before, but I don't think its too difficult
and the gaskets aren't that expensive either. Keep us posted. Good luck.

edit: Oh, I forgot to ask, did you re-torque the head bolts after you ran it?

http://www.marineengine.com/parts/j...urer=Johnson&section=Cylinder+&+Crankcase

FTB530 · Mar 29, 2012

Re: 25HP johnson

Jasper i didnt re torque the heads yet i only ran the engine for about three minutes,and saw the same problem so i had other things to do so i gave up on the engine for the day ,i am going to check the cylinders again and see if any water is in there and then i may remove the exhaust cover and look and re torque the heads,

P.S. i want to thank you guys for your help and information.

FTB530 · Mar 29, 2012

Re: 25HP johnson

No water in the cylinders after about a 5 minute run, less smoking then yesterday but it still is running rough,i think im going to take it to the river tomorrow and run it up stream and see what happens.

Johny25 · Mar 29, 2012

Re: 25HP johnson

Just remember it will always smoke more when run in a barrel or on muffs compared to being in a lake. Not sure how much smoke you are talking about though? Play with your slow speed idle screw on the carb and see if you can get it running a little better. About 1 and 1/2 turns out should be a good staring point.

FTB530 · Mar 30, 2012

Re: 25HP johnson

Well it is raining hard here so i wont be on the river today,but i got one more question,it has been a while since i used the boat my self and one thing i cant remember is that when the motor is running it is spitting water out of the two small exhaust ports on the underside rear of the motor,i cant remember seeing this before ,is that normal?

AlTn · Mar 30, 2012

Re: 25HP johnson

yes

FTB530 · Mar 30, 2012

Re: 25HP johnson

AlTn said:
yes

Thank you !!!!

FTB530 · Apr 3, 2012

Re: 25HP johnson

Well i finally got the boat out in the water,it ran good with the throttle open and it doesnt smoke any more then it ever did,but at idle its running pretty rough,has a bag cough once in a while.so im going to spray some carb cleaner through it and see what happens ,if that dont help ill buy a rebuild kit,thank you guys for the advice and help,

AlTn · Apr 3, 2012

Re: 25HP johnson

remove the carb before spraying it with carb cleaner..pay particular attention to the main jet < orfice plug >...recommend removing and cleaning it thoroughly as it has to be spotless

FTB530 · Apr 5, 2012

Re: 25HP johnson

AlTn said:
remove the carb before spraying it with carb cleaner..pay particular attention to the main jet < orfice plug >...recommend removing and cleaning it thoroughly as it has to be spotless

I think i gave up on working on this motor,maybe take it to the shop soon,.took it out again and it ran good for the first ten minutes, then would barley idle but wide open it ran like a champ, just after slowing down to half throttle it cut out bad and didnt run very good,time for a mechanic.

FTB530 · Apr 14, 2012

Re: 25HP johnson

Looks like i am still getting water in the cylinders,any one have any more advice what i should look at next .Thanks for any info .

Ps i bought another head and it is the wrong head,any one need one let me knwo ill put up a picture of it,

jasper60103 · Apr 14, 2012

Re: 25HP johnson

I hate to say it, but I think you're back to F_R's advice in post #6. Did you do a compression check?

Cofe · Apr 14, 2012

Re: 25HP johnson

Yep...F_R is right on. Those exhaust cover gaskets and baffle are known to fail on a aging motor. Disassemble it before ordering parts. If the baffle plate is warped, you will need a new one.

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