Problems dont seem to stop.

[Dame Doe]

I cant seem to win with this boat. I clean the fuel switch. Changed whatever remainder gray lines,new plugs. It ran great but after i came to an idle it would again just power up for 3-5 seconds then go back to idle. Im completely lost at this point. Help please....:ack:

 

[seadooya]

try pulling the choke, see if that wakes up the motor, if so, then you got carb/fuel delivery issue.

 

[scooper77515]

Also, those fuel switches are pretty cheap. I tried to clean one on my XP and had all kinds of problems with stalling, stumbling, etc. Swapped the switch and runs like a charm now.

Apparently, there was a slight air leak at the switch and I was losing my fuel system pressure through it.

 

[Dame Doe]

I tried the choke. It just shuts off when i pull it. Ill order a new fuel selector switch. Any other help ideas out there..

 

[seadooya]

did you go through the carbs?

 

[Dame Doe]

It has new carbs. I adjusted them according to repair manual. What I did notice the plugs are wet after any use.

 

[seadooya]

are the new carbs jetted to yuor boat specs? and/or the pop-off set to yuor boat?

 

[Dr Honda]

are the new carbs jetted to yuor boat specs? and/or the pop-off set to yuor boat?

:agree:

yup... what he said.

 

[Dame Doe]

Im not sure if they are jetted right. The guy i brought the boat from put them on and unfortunately i cant get in touch with him anymore. How can I check?

 

[Dr Honda]

You have to take them apart, and read the numbers printed on them. Also... the pop-off pressure is a very important adjustment. It's got to be right or the engine won't run.

Your single 720 engine should have....

130 main jet
67.5 pilot jet
40 - 56 psi pop-of
1.2 needle/seat

AND...
1-1/4 low Needle
0 high Needle

If your plugs are wet... you are running rich.


If you were closer to Pittsburgh... I'd give you a hand with it. You don't come out this direction for any reason, do you??

 

[Dame Doe]

Dr Honda. i dont come that way for anything but I could. Ill open them up and see. If I cant figure it out then ill come that way.

 

[seadooya]

if yuo can get them out, but are hesitant to open them up, mail the carb/s to him....:cheers:

 

[Dame Doe]

Sounds like a more realistic plan. Honda you ok with that?

 

[Dr Honda]

if yuo can get them out, but are hesitant to open them up, mail the carb/s to him....:cheers:

:agree:


Anyway... don't waste the fuel/time to drive to me. (or the turn pike fees) If you pay for the shipping both directions... I'll go over the carbs for you. PM me for an address.


OK... I went and looked at your old posts to see if I could find anything else. One thing I found said the engine only had 135 PSI in each jug. That is enough to make it run... but it's approaching the "Not Running" level. Please recheck the compression. Cold engine, open throttles.

I'll still look at your carbs, but that may be the issue.

 

[Dame Doe]

Ill check the compression again after work. I cant understand I just put a tranny in my Bimmer this weekend but cant get this F@%king boat right. Thanks for all the help guys. P.S. What should the compression be?

 

[seadooya]

What should the compression be?

perfect is 150psi

 

[scooper77515]

One thing I found said the engine only had 135 PSI in each jug. That is enough to make it run... but it's approaching the "Not Running" level.

How low does compression go before "not running"?

I assumed you could go pretty low and still run, you would just lose power. I figured you could dip into maybe the high 80s or so, as long as both cylinders were approximately similar.

 

[Dr Honda]

How low does compression go before "not running"?

I assumed you could go pretty low and still run, you would just lose power. I figured you could dip into maybe the high 80s or so, as long as both cylinders were approximately similar.

Out of the water... it will run with 90 to 100 psi. But, to have any noticeable power in the water (because of the load) you need 125 psi or better. When you go lower than that... when you open the throttle, the engine won't accelerate, and as soon as you don't have enough vacuum for the throttle setting, the engine will just shut off.

On an average car (with a 4-stroke engine) the carbs are VERY SMALL compared to what we run in the 2 stroke world. So, if you have 80 PSI in an old V-8 with a 2G Rochester... you can still get enough vacuum to draw fuel, and run. (poorly) Now take that same engine, and try to mount a Dominator on it... (or more realisticly, four IDF 44mm Webers) and it will step on it's d**K as soon as you open the throttle.

 

[Dr Honda]

Ill check the compression again after work. I cant understand I just put a tranny in my Bimmer this weekend but cant get this F@%king boat right. Thanks for all the help guys. P.S. What should the compression be?

It's a totally different set of rules. Don't feel bad about it... since you can turn a wrench... it's just a mater of learning.

And... as SeaDooya said... 150 psi is OEM spec.