150 bog problem

[hl]

I have a 1986 150 that bogs down after the first start of the morning. This bog will last from 10 to 15 minutes then it will run normally for the rest of the day. It only does this on the first crank of the day. The manual tell nothing about this problem. Just rebuilt the carbs thinking this could be the problem, but does not help. Does anyone have an idea what could cause this problem.

 

[Big flop]

Re: 150 bog problem

Can you post SER #?
Does it have a thermal air valve?
STB cylinder head with a hose that runs
to the carbs. It should richen the idle when
the motor is cold?

 

[Maxz695]

Re: 150 bog problem

did you adjust the air mixture screws correctly after the rebuild?

 

[hl]

Re: 150 bog problem

The boat is 30 miles away. I will check for a vaccum hose, but I do not remember seeing one when I took the carbs off. My manual said the fuel mixture was preset and there were no needles to adjust. I was thinking the enricher switch may be bad, but I hear a click when the the choke button is pushed; still could be bad. Any other ideas?

 

[j_martin]

Re: 150 bog problem

It's noisy in here.

Your engine has neither a thermal air valve or idle adjust screws. I'm assuming it's a V6 with WH carbs on it.

If it's an inline, or has different carbs on it, it would have idle screws.

This could be caused by low compression, wrong jets in the carbs or other carburetion faults, linkage and timing synchronization, bad parts, ie switchbox or idle stabilizer/advance module.

It sounds like it's running a bit lean, and would be more sensitive to it when the engine is cold. It could have been "tuned" by someone looking for performance on the edge of destruction, and that's why you need to investigate the numbers and specs, especially jetting. Jet sizes differ widely on different carb models.

 

[hl]

Re: 150 bog problem

Looking at the pistons, thru the spark plug hole, they appear to be a dark color. Would the pistons appear to light to white color if it was running too lean? Should I have someone check the timing(Which I have never done on an outboard?

 

[Maxz695]

Re: 150 bog problem

ear plugs are cheap J but thanks for helping the man

 

[Faztbullet]

Re: 150 bog problem

It's noisy in here.

 

[hl]

Re: 150 bog problem

I forgot to mention the compression shows 120-123 in all cylinders. Also used ears on the motor after the carb work;Sounded great but did not push RPMs too high. On first start the motor revs up good but after puting it in gear is when it seems to bog.

 

[j_martin]

Re: 150 bog problem

I forgot to mention the compression shows 120-123 in all cylinders. Also used ears on the motor after the carb work;Sounded great but did not push RPMs too high. On first start the motor revs up good but after puting it in gear is when it seems to bog.

With that info, look up the linkage adjustment and timing sequence and perform it. It is a little intimidating till you figure out what in heck they're trying to do, but it is to check your timing mark, then adjust timing and linkage to spec.

If that don't do it, it's time to dig into the carbs.

hope it helps
John

 

[hl]

Re: 150 bog problem

I will study the manual for the timing. It will be next week before I get a chance to check the motor again. Let you know what happens. Thanks for the advice.

 

[CharlieB]

Re: 150 bog problem

A shot in the dark,

While STONE cold and motor OFF, disconnect the throttle cable at the motor and open the throttle to WOT, watch the timing lever to ensure it is moving freely to the max advance timing stop.

Resoning: If the timing is sticking while cold, the motor will not accelerate, but once warmed a bit the trigger plate 'frees up' and allows movement.

 

[hl]

Re: 150 bog problem

Just as CHARLIEB mentioned in the above post, I checked the timing arm while the motor was cold, and the arm did not seem to move freely. After fishing for a while checked it again and the arm seemed to move more freely.What is the solution?

 

[j_martin]

Re: 150 bog problem

Just as CHARLIEB mentioned in the above post, I checked the timing arm while the motor was cold, and the arm did not seem to move freely. After fishing for a while checked it again and the arm seemed to move more freely.What is the solution?

Free it.

Something is binding, either in the throttle arm linkage, or the trigger itself.

Often it is in the harness from the trigger, which has to be on top of the pile and free to move with the trigger.

A wrong screw mounting the stator can also interfere with either the harness or the linkage of the trigger.

Oil and dirt can also interfere with free trigger movement.

hope it helps
John

 

[hl]

Re: 150 bog problem

I have a friend, who is more experienced in outboards,that will show me about the timing and the sticky lever. I will let you know what we find. Thanks for the info.

 

[hl]

Re: 150 bog problem

Finally got around to timing the motor with the help of a friend. He spotted the sluggest timing lever and cleaned around the movable parts. Also set the low end timing. the motor runs much better. Thought this information may help someone in the future. Thanks for the advice.