1979 80hp four, SN# 5378620, running issues, Carb related?

[highsider989]

I just put my new old boat in the water and it pretty much ran real bad, idled ok once warm, would stall occasionally when put in gear, would run to 1/2 throttle, would bog and stall over that.The boat never got on plane..Boo.

I had a full tank of new gas mixed at 50/1, the bulb did get hard at prime. I"m not sure the electric choke solenoid is functioning. How do i check that the tank vent is functioning?

Suggestions for starting cleaning the fuel system, fuel filter first, water separator, carbs?

Thanks!

 

[Chris1956]

That motor should have a fuel screen on the fuel pump. It makes sense to clean it. A built in tank will have a vent on the side of the hull. Look for it. On a portable tank, you will normally see a thumbscrew to open the vent. If in doubt, loosen the fuel tank cap for testing. Push the choke button and listen for a click. If no click, the choke is likely not working.

Starting procedure: Lift cold start lever all the way. Pump primer until hard. Hold down choke button and crank motor until it fires. Feather the choke until she is warm.

 

[highsider989]

pulled the carbs, cause i'm a small engine guy, I found a real soft spongy float set in one of the carbs, that makes sense in the way it was running. The carbs look clean and the fuel strainer before the carbs was clear. I'll order a rebuild kit for the carbs and pray that the bad floats is the issue....

Thanks Chris, I also need to check the choke solenoid for continuity. I can't pull it out with out pulling the flywheel, thats kinda stupid..

 

[Chris1956]

Gee, Doesn't the choke solenoid come off with the top cowling support? It should be three 3/8" nuts on top and six 1/2" bolts to remove it, plus the choke wire. After you get the carbs clean, if she still won't rev up, ohm out the high speed stator winding.

 

[highsider989]

Been busy, new floats go in Saturday. No to find time to get the boat in the water again.

 

[highsider989]

floats are in, carbs clean and the screen was clear, now the primer bulb wont get hard, engine starts and runs but soon runs out of gas. Ive got a new primer bulb, it has hose a larger inner diameter than the old one, does this matter?

 

[highsider989]

the auto choke is not working either

 

[Chris1956]

That motor has an electrical choke. You must push and hold the choke button for it to operate. It is only usually necessary for initial cold start.

If the primer bulb will not get hard, it is either defective, sucking air, your carbs are flooding or the fuel pump diaghram is leaking. Do you see fuel in the water?

 

[highsider989]

No Title

Oh shoot! One step forward one step back. I replaced the primer bulb, it works great. The motor was a bit hard to start and get warm but I finally got it running well enough, I backed out on the idle mixture screw a half turn each and once warm it runs good, it seems it'll idle all day, perhaps a bit high but something else happened. I had the muffs on and the motor was idling for about 10 minutes, as I was watching I saw a white wiff of smoke coming from the switch box. I turned the key off and the motor didn't shut down! Crapola! I had to disconnect the fuel hose. It continued to run for a while longer till the fuel in the bowls was used up and no more smoke. I'm very concerned about not being able to shut the motor down with the key, Any ideas? As for the switch box, I'll pull that and investigate? Any way to test the box? I don't see a melted wire from the spot that got hot but it did melt some of the plastic insulating stuff in the box.

So on to another system on this motor, ugh, at least the fuel system is now good. I just need some minor tuning, check the idle speed.

The electrical stuff isn't that intimidating but some advice from someone with experience would be great, Thanks in advance.....I'll try to post pictures.

 

[Chris1956]

I would make sure the grounds on the switchbox are clean and tight. Make sure the orange wire on the switchbox grounds when the ign key is turned off.