Chrysler 55hp (555HD) won't start

[ac439]

I have been working on this outboard for a while trying to get it started but no luck so far. The motor was in storage for around 3 years.

I have opened the carb and clean it up really well. Got the gummy stuff out and have sprayed the injecter cleaner through the jet nozzle to ensure openess. I have adjusted the float according to the spec. Over at the fuel pump, I have cleaned the glass bowl and the filter screen is clean. I have also opened the fuel pump and checked the diaphrams for air tightness. I have also replaced both the vacuum hoses between the fuel pump and the engine. I have also checked the three valves on the fuel pump and the springs are not sticky and return them to the close position. However, I can't verify if the valves are sitting tight when they are closed. After these, the best I was able to do was to have the engine started and run for 6-7 seconds and it stalled.

I have checked the spark plugs, files them and gap them back to 0.03" spec. Still no luck.

There are some weird things I have noticed during the course of the troublshooting. At the carb, there is a 1/8" hole (horizontally facing outwards) at the driver side at the top of the throttle body. It opens to the float chamber. I wonder if there should be a plug but fell off. I do see other small holes over the carb body but they are all plugged and closed.

Also when I took the spark plugs out, they seem to be wet. I know the 2 cycles need wet oily fuel for lube. But I wonder if the engine is flooded?

I also noticed that the prime pump still kind of firm after many fail start attempts. I wonder if the prime pump is not working right or the fuel pump not really pumping fuel to the carb?

Being Sunday today, all boating shops are closed nor can I get the rebuilt kits from NAPA. I'm lost and not sure where to start again. Any advise is appreciated. Thanks.
-AC

 

[steelespike]

Re: Chrysler 55hp (555HD) won't start

You said 0.03 on the plugs I assume you mean .030.Usually those carb holes are from drilling out for passages.And there are little plugs in them.
You need to be really careful trouble shooting the ignition. Improper procedure can damage the system.Pull the gas line from pump to carb and
CAREFULLY crank it with it in a can.Fuel should come out in strong steady pulses.With gas tank connector unhooked CAREFULLY spray fuel mix into the carb throat to see if it will fire.
Check spark with a proper spark checker,Should jump at least 3/8 of an inch.

 

[Frank Acampora]

Re: Chrysler 55hp (555HD) won't start

First: that IS a vent hole and keeps the carb bowl at atmospheric pressure so the venturi can function properly. Do Not Plug It!.

2nd: It still sounds like a fuel problem. Did you remove the low speed adjusting needle and spray cleaner through its passages? When you try to start the engine, only the low speed circuit is functioning. If it is clogged, the engine will start and run until the choke prime is exhausted then die.

To confirm this, once you start the engine, before it dies, intermittently and momentarily repeat closing the choke. If the engine keeps running as long as you do this, then the low speed circuit is not delivering fuel.

If this is so, remove the brass needle and spring from the top of the carb, spray cleaner throught the passages and replace the needle and spring. you may also need to remove the carb bowl and carefully run a fine wire and cleaner through the small diameter brass tube that runs from the bowl to the top of the carb. This supplies the low speed circuit and if gummed or clogged, obviously no fuel will get to the engine. Start with the needle turned out 1 1/4 turns from lightly seated and adjust as per the manual.

The button valves in the fuel pump sound like they are working correctly, but did you replace the diaphragm? Should be flexibile and supple. They get stiff and hard when they get old. New one only costs about 3 bucks. To double check the fuel pump, once the engine starts, keep squeezing the fuel bulb. If the engine keeps running, the pump is not delivering fuel.

 

[eurolarva]

Re: Chrysler 55hp (555HD) won't start

Spark plugs should be L82C gapped to .030 inches. Fuel mixture screw in front on top of the choke butterfly is all the way in then back it out to about 1 1/4 turn. The three small holes you mentioned that are covered by the welsh plug will be for your idle. I would remove the mixture screw and shoot some carb cleaner into where the screw was then replace the screw and reset to 1 1/4 turn. NAPA sells the carb kit 18-7037 and the fuel pump kit 18-7806. Typically the carb kit is same day where the fuel pump kit takes about a week to get. I would get the pump kit for it is only 9 bucks. Iboats sells both of these kits for the cheapest I have seen anywhere. The diaphram inside the fuel pump may look good but if it is original it is worth replacing. I replace mine every two years because of the alcohal in the gas.

 

[ac439]

Re: Chrysler 55hp (555HD) won't start

Thanks for all the replies ! I just did a little more troublshooting this morning and believe this is still the fuel problem. After reading the replies here, I think it's my low speed circuit causing the starting problems.

First, I re-read the manual and found out that I should have advance the throttle until it stops with the gear in N. I primed the ballon and started the engine. It started much stronger but stopped in 2 seconds. So, I think the ignition is fine and only the first batch of fuel from priming the ballon fired the engine and then engine stop after it was used up. The low speed circuit did not continue supply fuel.

I'm going to NAPA before I go to work today to order the kits for rebuilding the fuel system. I think I'm getting close to fixing the engine. I am going to post the result here when I can get back again to work on the engine on Wed.

thanks a bunch !
-AC

 

[ac439]

Re: Chrysler 55hp (555HD) won't start

I can't wait till tomorrow to work on the boat so I was up early this morning. Still won't start, but I'm getting close to the source of the problem (fuel):

I had opened the low speed screw and the carb bowl and sprayed carb cleaner. I noticed all passages are clear. When I opened the carb bowl, I noticed that there is almost no fuel inside. The float lowered by gravity but the inlet needle DOES NOT lowered. So, I cranked the engine and there is no fuel coming through the inlet needle valve. When I lowered the needle valve by hand and crank the engine, I had fuel pumping through. I took out the needle valve and the seat and inspected them. They are very clean. The very tip of the needle is coated with orange rubber. After I put the needle in and seated the tip, the tip will not open by gravity. So the valve is stucked ! I believe the orange rubber material might have been deteriorated.

When I opened the fuel pump yesterday and inspected the diaphrams, they are not very soft but they do maintain a seal. I'm going to pick up the carb kit today and see if that would fix the problem. If not, the fuel pump kit will be next. Hopefully, the engine will run after these.

Thanks !
-AC

 

[Frank Acampora]

Re: Chrysler 55hp (555HD) won't start

There's your problem. A rebuild kit with new needle and seat will solve it.

 

[ac439]

Re: Chrysler 55hp (555HD) won't start

Motor is running !!! Motor is running !!! Motor is running !!!!!!!!

I have the rebuild kit so I took out the carb and did a close inspection. First of all, I replaced the needle valve. The new one will drop by gravity so I know I'm good with the new one. After that, I looked very closely at the small brass tube that dip into the bowl. I found a hair line crack for about 3/4" along it's length so it is sucking air. I put it on a bench and warmed up my 60w soldering iron, filed the brass tube shinny gold and closed the crack with solder. After that, I check for patency by spraying carb cleaner through it.

I put the carb back to the engine, prime the ballon and started it. It started much stronger but still stopped within 10 seconds. Then I figured out I forgot to put the idle mixture screw back. After putting it back, seat it all the way in and counter-clockwise for 1 1/4 turns, the engine starts ! A minute later, I put the throttle at the middle (Neutral pos) and the engine died. Upon messing around with the idle mixture, I was able to maintain engine running at idle for 20 minutes without any problems. At this setting, the idle screw was about 3/4 turns CCW from fully closed position.

I saw water (like a shower) coming out from the exhaust hole. I also noted water being pushed out behind the water inlet so I think I'm good. At one time, I saw water passing through the clear tube (connects at the thermostat) but it disappeared afterwards.

One thing I notice is there is no O-ring for the idle mixture screw. The rebuilt kit also doesn't come with one for it. Isn't there suppose to be an o-ring at the idle mixture screw??? (at least my car has an o-ring for the screw).

I'm so much more happy and thanks to you all for the help !!!!
-AC

 

[eurolarva]

Re: Chrysler 55hp (555HD) won't start

Nope on the oring. Just a spring and a screw.