No power

[gregory62]

I have a 20HP chrysler built in 1975-76. I replaced the blown head gasket. Now it doesn't seem like it has the power it should. Other than that it runs good. Compression on both cylinders is just above 90. Does anyone have ideas or suggestion on what I could try? Do you think it could be the carb. just needs adjusting?<br />thanks for any ideas.<br />Greg

 

[eurolarva]

Re: No power

90 compression seems a bit low. My guess is it should be around 120. Did you test it on a warm engine or a cold one? Try squirting some oil in each of the cylinders and re try compression. What type of spark plugs are you running? If it is a straight 2 cylinder with a magnapower ignition try using L82C plugs. Book says it works on all except 20 HP Series 2000 motor what ever that is. Please post your model number so I can cross check the plugs. <br /><br />When running try disconnecting a plug wire and see if it changes the performance. You might only be running on one cylinder which would explain the lack of power. If one cylinder is not firing you should also notice it on the tips of the plugs. The cleaner of the two plugs would be the suspected cylinder. It could be carb or fuel pump however this sounds more compression or spark related.

 

[gregory62]

Re: No power

I checked the compression on a cold engine. I will check the type of spark plug tonight. They should probably be replaced. I did check spark in them and they both have good spark. The model number for the motor is 203HG.<br />Also, and I don't know if this has anything to do with the problem, but the two small holes on the lower unit down by the prop. have oil that oozes out of them after running the motor.<br />I will also check to see if it is only running on one cylinder tonight also.

 

[eurolarva]

Re: No power

The oozing stuff out the exhaust holes in the lower unit is normal. A decarb may help this however if you are not firing on a cylinder it will do this also. I dont know what type of recirulation system your motor has. Older models drained unburned gas out the motor leg. Newer models have a recirulation system that is suppose to reburn the gas. If you have the later you might want to verify the screens are clean for this system. Please post your model number.

 

[gregory62]

Re: No power

I am pretty sure that I have the older model that drains the unburned gas out th motor leg.<br />the model number is 203HG

 

[eurolarva]

Re: No power

1975 is the year. Online parts places only go back as late as 1978 so I cant tell by looking online. My guess is that it has a recirulation system. If your motor runs good I would go to www.chryslercrew.com and buy a downloadable parts manual for that motor. It will tell for sure. Mine is 1967 and I had to drill a hole in the lower cowling and attach a plastic bottle to catch the gas draining into the leg. It was embarrasing at the landing when I was putting gas into the lake.

 

[gregory62]

Re: No power

Well I put oil in the cylinders, now the compression is up to 115 on both. Is that something that needs to be fixed, or do every once in a while. <br />I ran it and disconnected the spark plug wires, and both effected the running of it.<br />On one spark plug, the gap was really small, so I looked in the book and regapped them. Is that something that would effect the performance of the motor, could that have been my problem?<br />I am going to buy new plugs tonight. The plugs that are in there are AC 42F. Anyone know if they are the right plugs or something better to use?

 

[eurolarva]

Re: No power

The plugs that chrysler originally speced out is L4J which is no longer availible. Get Champion L86C plugs and gap them at .030 inch. Napa sells them for about 2 bucks a piece.<br /><br />Adding oil to the cylinders is not a fix but a test. The test shows you have something wrong with the rings or the pistons or the cylinders. Adding oil will increase compression by helping seal the rings. I dont have the specs for compression on that motor but my 45 from 1967 still blows 145 in both cylinders. You could try rebuilding the carb and fuel pump but my guess is that your compression is low and not providing enough push on the atomized gas to create sufficient combustion. I would get a second opinion on this. Good Luck.

 

[gregory62]

Re: No power

Thanks for the information. I will be taking the boat out over the weekend and trying the motor again. Hopefully it will work good, if not I will probably sell it on EBay. Sometimes it is just time to say enough and buy a newer one that is more reliable. I will buy the new spark plugs and see if that helps at all. <br />Thanks eurolarva for your help, you really know your motors.

 

[gregory62]

Re: No power

Well I tested out the motor over the weekend, it really doesn't run any better than it did before. At least no more power than was before, it does sound alittle smoother. would it hurt it to run the motor this way? could something give way and leave me stranded out on the water?