Only getting 1/4 power out of my 55hp

[Galaxie]

Hello all, I had my Charger 118 with its trusty 55 HP ('71 555BC)out on the lake last week and had a rather interesting problem. When in neutral the engine will rev. right up till it screams, but in gear I can only get about 1/4 the revs and thus 1/4 the speed (a bit embarrassing) . It's purring like a kitten, but about as fast as an old dog.<br />I find it rather odd that it will scream in neutral, but only produce about 800 RPM in gear. I think it’s the fuel pump. Has anyone heard of this problem and could offer some advice as to how to rectify? Thanx.

 

[scotiany]

Re: Only getting 1/4 power out of my 55hp

I have a '70 55 hp. I think your analysis about the fuel pump is an excellent place to start. Cheap and easy to replace diaphragm. Another thing I'm wondering. Could the high speed jet in the carb be plugged?

 

[Galaxie]

Re: Only getting 1/4 power out of my 55hp

Thanx. Scotiany, I'll get moving on the fuel pump, but I had a question about the high speed jet you mentioned. I have a shop manual on the engine and there is no mention of a 'high speed jet'. Is this the 'main fuel jet'?

 

[scotiany]

Re: Only getting 1/4 power out of my 55hp

Yeah, I guess that would be it. Main jet and idle jet or high speed and low speed-same thing. I assume you have the Tillotson WB carb. It's easy to take apart, clean and rebuild. The carb kit is readily available and comes with good instructions. It's about $15 US. The fuel pump kit is less than $10. Couldn't hurt to do both.

 

[eurolarva]

Re: Only getting 1/4 power out of my 55hp

Iboats sells the pump kit here is a link chrysler fuel pump kit <br />Also check your spark plugs and verify both are firing. Check to see if the tips on both plugs look the same as in dirty. If you have the ability to get the compression tested. YOu may be running on one cylinder.

 

[Galaxie]

Re: Only getting 1/4 power out of my 55hp

The carb and the fuel pump are clean and free of any defects. After inspecting both, reassembling, and reinstalling the engine revd up fine in neutral and in gear. Hooray!!! BUT WAIT!! After about 10 mins when I tested it again it would only rev up to about 800 rpm. I took eurolarva's advice and checked my plugs only to discover the lower plug wasn't firing again. I recently replaced both points and condensers and gapped to .020. I had the coil that fires the lower plug tested and it passed. One thing I noticed when I rechecked my point gaps is that the points for the lower plug were at .025 so I reset them to .020. By the time I got back to rechecking for spark both plug weren't firing!!! I think this is because I've run down the battery. Any words of wisdom would be greatly appreciated as I continue to trouble shoot.<br />Thanx. All.

 

[scotiany]

Re: Only getting 1/4 power out of my 55hp

Do you know if the puddle valves have ever been removed and cleaned? It might not be your major problem but, it can contribute poor low speed performance. Check the post from 1badchrysler85. His puddle valves were all crudded up. This will cause an overly rich mixture usually in the lower cylinder to the point where it won't fire at all .

 

[Galaxie]

Re: Only getting 1/4 power out of my 55hp

Thanx. scotiany, Where are the 'puddle valves' located?

 

[eurolarva]

Re: Only getting 1/4 power out of my 55hp

Hey Galaxie. If you have a parts breakdown for you powerhead the pudddle valve is the drain reed plate

 

[Galaxie]

Re: Only getting 1/4 power out of my 55hp

I've taken my coil, points, and condenser and flipped them to the the other sides. Now the lower plug fires and the upper is dead. So I have confirmed that both coils, points and condensers are working. Is there something before these I should be looking at?

 

[eurolarva]

Re: Only getting 1/4 power out of my 55hp

Try just swapping the coil. I doubt it is the points. I am guessing the coil is bad. Can you ohm it out. I believe the resistance should be around an ohm on the good coil. A bad coil will show no resistance, high resistance or a short. good luck

 

[Galaxie]

Re: Only getting 1/4 power out of my 55hp

Thanx. eurolarva, before I did the full swap I did just the coil and there was spark. So both coils are delivering spark. I have two points, and two condensers that I have confirmed fire on the one side. That's why I think it's something before the electrical under the flywheel. I noticed in an earlier post a mention of a wire similar to lamp wire that runs from the points to the electrical block. The wire from the points on the side I'm having a problem with connects to a blue wire which runs up the wire harness to the ignition switch. Does any one know the purpose of this wire and could this effect the firing on this side?

 

[eurolarva]

Re: Only getting 1/4 power out of my 55hp

I dont know the electronics on a motor. I looked in my manual and the blue wire looks like it is for a over heating accesory. If that isnt it it might be some kind of kill circuit to shut the motor off. My clymor and factory manual does not mention what this wire is for or what it does. Hell if nothing else this thread got bumped back to the top and maybe someone like alcan would know the answer.

 

[Galaxie]

Re: Only getting 1/4 power out of my 55hp

I tracked back that blue wire to the ignition as I mentioned before and I noticed another blue wire from the ingnition to the tach. Well this tach hasn't worked since I bought the boat so I disconnected it and... Voila! Spark!! Well what do ya know. Now I just have to locate a replacement lockdown washer for the flywheel which I ended up stripping with all the on and off of the flywheel. Thanks all for the input and advice. It's great to have iboats and the members forum to bounce ideas off of.

 

[eurolarva]

Re: Only getting 1/4 power out of my 55hp

Glad to hear it is working. As far as I can tell on my manual the tach circuit is a white wire that should be going back to your condensor. There should not even be a blue wire going there. Unless I have the wrong electronic schematic a white, brown and black wire should be going there. Before you get it all put back together try running it with muffs. If the motor can not be shut off with the key use a rag and stuff it into the carb choke to kill the motor. Just in case this is a motor kill switch.