Outboard bogs down when in gear...help!

[smsscuba]

I have a 1998 3 cylinder Johnson 35hp (BJ35ARLECR) that when put into foward gear, only gives low,limited revs on full throttle.I can get full revs when in neutral.

I removed all three sparkplugs and checked for spark.All three coils do produce a nice blue snapping spark, also I noticed that the top sparkplug was the only one that was slightly discoloured.The other two were still shiny (note these are brand new plugs).There was an oily mix on all three plugs, so they must be receiving oil/fuel mix.It wants to give more revs but something is holding her back.

Does the problem maybe lie within the carbs when under load.Can someone point out to me where to start looking? I have removed the carbs and looked in the bowls.All are spotlessly clean.

Maybe someone has had the same problem as me in the past.

Regards

 

[dew2]

Re: Outboard bogs down when in gear...help!

Have you looked at the lower unit,Maybe lots of line in there or some kind of obstruction.

 

[smsscuba]

Re: Outboard bogs down when in gear...help!

I have removed the prop and regreased the shaft.The prop does spin freely.In gear the engine only gives a restricted amount of revs.Something is preventing full throttle.The carbs smell very like petrol, maybe the cylinders are flooding, thus preventing full throttle.The question is, where do I start looking?

 

[Cofe]

Re: Outboard bogs down when in gear...help!

Replace the fuel filter and check the ventilation system on the fuel tank.

Your motor should not be able to go max rpm in neutral. There is a throttle linkage system that is supposed to prevent that. If you are getting max rpm in neutral you are setting yourself up for a run away motor, and it will self destruct.

 

[steelespike]

Re: Outboard bogs down when in gear...help!

The clean plugs could be an indication of a bad head gasket.Water getting in the combustion chambers.Do you see any water droplets or rust on the pligs?Also the exhaust would produce white smoke/steam that would hang in the air.

 

[smsscuba]

Re: Outboard bogs down when in gear...help!

When I initially removed the plugs, there was no indication of water ingress into the cylinders. Only a petrol-oily mixture. I've still got the suspicion that something is causing it to flood on the two lower cylinders. On my Johnson controls, I have a fast idle which you can operate in neutral, not taking it to max but definitely taking it to high revs. As soon as it goes into gear, the revs are limited.

 

[dew2]

Re: Outboard bogs down when in gear...help!

New engine to you? Did it run fine last year or whenever you last ran it?

 

[smsscuba]

Re: Outboard bogs down when in gear...help!

Thats the problem my friend, it IS a new engine to me.I have not personally used the outboard as of yet.Only found this problem out today when I wanted to start her up in salt water.I backed the boat up, still tightened to the trailer into the water untill the lower leg was submerged.

The revs would not pick up, even when full throttle position was attained.I noticed the motor would try to pick up a rev or two, but nothing over 2000ish rpm and a lot of petrol in the water.

 

[dew2]

Re: Outboard bogs down when in gear...help!

Think I'd start looking at the carb,Maybe a kit.Single carb on it Right??
Cant hurt and who knows how dirty it is.

 

[smsscuba]

Re: Outboard bogs down when in gear...help!

It has three carbs, opened them all, checked both idle passage oriface and high speed oriface.Blew compressed air throughout.The carbs internally and externally are so clean, one could eat dinner off them!

 

[jonesg]

Re: Outboard bogs down when in gear...help!

A couple of things can flood it, stuck choke or floats not closing off the fuel inlet to the bowls.
If the bulb does not pump up firm the bowls are flooding.
Remove a carb, drain the bowl and put a short length of line on the inlet nipple.
Blow through the line and flip the carb upside down, you should not be able to blow through the line if the float needle is seating properly.
New to you, it would make sense to order 3 rebuild kits for the carbs, maybe a water pump impellor too.

 

[dew2]

Re: Outboard bogs down when in gear...help!

I dont know about sync but have you looked to see if they all respond in unison when at a certain point lined on the flywheel?
My belief is you have a fuel problem.Whats it take for a internal combustion engine to run? You have spark. It starts but when under load and it needs fuel its not getting any?

 

[boobie]

Re: Outboard bogs down when in gear...help!

Have you checked the spark on all three cyls? Backing a boat in the water on a trailer and having the boat still on the trailer will never give you full rpm with the mtr unless you have a test wheel on it. Take it off the trailer and give it a good run.

 

[78 mckee]

Re: Outboard bogs down when in gear...help!

Have you checked the fuel pump for a ruptured diaphram? Remove the pump from the block and put nuts on the screws that attach it to the block. Tighten the screws and then pump the fuel bulb. If fuel leaks out of the rear port on the pump, rebuild or replace the pump. Fuel leaking through the diaphram runs right into the crankcase and floods the cylinders in fuel.

 

[kevin11mic]

Re: Outboard bogs down when in gear...help!

I would rebuild the carbs clean them with rubbing alchoal then blow compressed air through any hole you can find in the carb. Reinstall all the carbs and set them all the same. Check all your fuel lines for leaks and might clean the filter/pump.

 

[boobie]

Re: Outboard bogs down when in gear...help!

??? What's the compression on it. Does it still have the oil tank on the mtr.

 

[smsscuba]

Re: Outboard bogs down when in gear...help!

I test it cold ( I know, should be warm!) and get 105psi on all three cylinders.Tonight I peeked through the plug hole and found all three cylinders score and scratch free.They look to be in a good condition.The oil tank has been bypassed and now premixed 50:1.

 

[boobie]

Re: Outboard bogs down when in gear...help!

Smart move by removing the oiling system on that mtr and mixing 50:1. Now, did you ever try the boat on the water by taking it off the trailer??????

 

[jonesg]

Re: Outboard bogs down when in gear...help!

??? What's the compression on it. Does it still have the oil tank on the mtr.

Compression is good.

When you checked spark, did you use a spark tester set at 7/16th inch gap?

 

[smsscuba]

Re: Outboard bogs down when in gear...help!

i got the missus to hold the sparkplug in the bootrubber about 1/2 an inch from the motor body. All three coils produced a bright blue/purplish snapping spark. ( she wasn`t too impressed)