Pulse ? vacume? Preasure?

[robin savell lloyd]

What do you think? I was out riding around on my boat today and began to lose power. dumby me I kept going for less than 5 minutes hopeing the problem would go away. that was a stupid choice on my part I beleive. I should of stoped as soon as I seen a problem. Well any ways I found that I had a pulse line had a kinck in it. Luckly I bring all hoses with me and I replace it with a piece 2 foot long. Way longer than what was needed. This is a pulse line and if I am not mistaken a pulse line needs to have preasure and allso be abel to let loose of the preasure every revalution. So I am thinking that a pulse line that is to long can cause problems. It would be like adding a tank witch would be good if it was a vacume or a preasure line but that it is a pulse line it has to go both ways and if the system is to big then it would loose its ability to do what it does pulse. Can any one else repliey to this issue? :cheers:

 

[kustomkarl]

Uh...just cut the Pulse line to proper length and be done with it. It needs to be a short line to the carb to work.

Karl

 

[robin savell lloyd]

This boat has [2] 44 mikuni carbs with a external pump and I am sure that you know that the 44 allso have fuel pumps in them as well did someone over kill this engine with the external fuel pump? should I remove it ? this is how I bought it. :cheers:

 

[derek]

i think with the volume of crankcase gasses being compressed, the volume of the extra foot or two of line would be negligable. but, having the pulse run back and forth down the long line could cost some. that might be where the compressability of the air in the line could hurt. robin, what motor do you have in there? 650 or 720?

 

[kustomkarl]

I believe in that year the external fuel pump was standard as the pulse line aids in moving fuel to the return line, but the external fuel pumps, pump the fuel to the carbs.

Leave it like it is.

Karl

 

[robin savell lloyd]

I have the 657x engine I could be wrong but I do not beleive that this pump came stock as it does not look like the type of work the factory would do. but may be some one who realy did not care as how it could be mouted. I beleive the factory would have mounted it beter to the hull. All the pulse lines allso have zip ties as hose clamps. seems shaby to me. :cheers:

 

[seadoosnipe]

External fuel pumps?....

Robin, the external fuel pumps were used in a couple different models but from what I see, your boat is not one of them. Your only suppose to have the body assembly pump, attached to the carbs as seen in the parts diagraphm.

The idea of more hose, creating more volume for the pulse line, is on track. This line is meant to pulse in and out with the stroke of the piston. If the hose is real long, when the engine first starts, it would have to pulse long enough to put the required pressure in the line and then, release it.

So, I see your idea. But, like derek points out, it may not be enough to notice. There has to be some length that you would find to long for sufficient operation........but who knows?

 

[robin savell lloyd]

Thanks for all the replies. I am going to shorten the pulse line a little so that it does not look to long. I was having a problem starting the engine in the water after I repaired the kinked pulse line yesterday. It allso seem to have lost a litle power once I finaly got it started. I hope that a lean condition did not take some compression from the cylinder that was not geting the correct pulse. I am going to give it a compression test today and find out :cheers: