Motor idels great but bogs when accelerating under load

[danielw71]

1987 3.0L MerCruiser with 2BBL Mercarb.
Just rebuilt carb, new plugs, wires, cap, Roter & Points. Fuel filter is clean & timeing is set at 6 deg BTDC @ 700 RPM dwell is 30.

Here is a video I posted to show what it is doing:

http://www.youtube.com/watch?v=wnfmH0dhzqs&feature=youtu.be

 

[tpenfield]

Re: Motor idels great but bogs when accelerating under load

Welcome to iBoats . . . very good idea about posting a video . . . it makes things soooo much easier.

That engine sounds 'interesting' . . . valve noise maybe? I would run a compression test and even a cylinder leak test, just to see what is going on from an internal perspective.

 

[danielw71]

Re: Motor idels great but bogs when accelerating under load

I am going to try to get the gauges to do that today.
Yesterday I tried spraying carburetor cleaner around the intake to see if it was sucking air and it is not.
I took the fuel pump off and looked at it and the filter and diaphragms are fine too.
A few weeks ago I took the fuel line off of the tank and put it into a gas can full of fresh fuel and it did the same thing.
I will post the results of the pressure test as soon as I get it done.
I would think if there was a bad cylinder it would be hard to start or run rough all of the time, it starts right up and idles great the bogging only comes in under acceleration.

 

[MBAKER]

Re: Motor idels great but bogs when accelerating under load

maybe double check that plug wires are in order?

 

[danielw71]

Re: Motor idels great but bogs when accelerating under load

Thanks, I will check when I get home but I am pretty sure they are right:
1-3-4-2

 

[danielw71]

Re: Motor idels great but bogs when accelerating under load

Yes 1-3-4-2 wires were right
still trying to get my hands on guages for compression testing

 

[danielw71]

Re: Motor idels great but bogs when accelerating under load

I took the distributer apart down to the advance weights and it was dirty and tacky. I could move the weights but it was not easy, so I cleaned them up, put a couple drops of 3 in 1 oil and put it all back. For the first time I could accelerate without the bogging I have not put it on the water to be sure. I will let you know if is all worked out. Thanks again.

 

[garbageguy]

Re: Motor idels great but bogs when accelerating under load

I took the distributer apart down to the advance weights and it was dirty and tacky. I could move the weights but it was not easy, so I cleaned them up, put a couple drops of 3 in 1 oil and put it all back. For the first time I could accelerate without the bogging I have not put it on the water to be sure. I will let you know if is all worked out. Thanks again.

Did that resolve your issue? I have a similar situation.

 

[danielw71]

Re: Motor idels great but bogs when accelerating under load

Yes!
I am sorry i did not get back sooner. I went out and was pulling two tubes and had no trouble, its running great now.