20 hp chrysler no high speed

[gregory62]

I have a 20 hp chrysler 19??<br />when in the garage in a garbage can the motor runs great, but out on the lake it won't give me high rpms. at best I can get high idle out of it. when there is a load on the engine, it won't rev up. I was thinking it might be something with the carb.<br />Thanks <br />Greg

 

[eurolarva]

Re: 20 hp chrysler no high speed

Hello Gregory. Great state you live in . It could be your carb or even a fuel pump or something wrong with your fuel line however I would test the compression first. This is also a symptom of a problem with the head. If you dont have a compression tester they cost about 30 bucks at sears. Pull the spark plugs out and see if both spark plugs looks kind of grimy and maybe have a slight oil residue on them. This would be a good sign. A bad sign will be one spark plug clean and the other dirty. Also post your model number. It should be on a small metal plate located under the carburator need the cowling lock.

 

[gregory62]

Re: 20 hp chrysler no high speed

I cleaned the carb last night and sprayed carb cleaner where the spark plugs go. After I ran it again I checked the spark plugs, the top one was dirty, grimy like you said, the bottom one was clean. I will post the model number tomarrow, I have to go and check on it. Do I have a new anchor or can something be done?

 

[eurolarva]

Re: 20 hp chrysler no high speed

Clean spark plug could mean a blown head gasket which is simple to fix. I would get a compression test done on it before dumping any money into and also test for spark. I live in brooklyn park so if you are close you can borrow my compression tester.

 

[gregory62]

Re: 20 hp chrysler no high speed

Thanks for the offer on the compreesion tester, but I bought one last night. the top cylinder is at 105 and the bottom one is at 60. I tested the spark, and it seems to be good. The model number on it is 203HG. Does anyone know what year it is?

 

[eurolarva]

Re: 20 hp chrysler no high speed

The 203HG motor was produced in 1975 and 1976. Compression number on number 2 is pretty bad. Hopefully it is just a head gasket. I tried searching for that head gasket and can not find one for a head going back that far.I believe the gasket for a 1978 20 HP will work on that motor and the mercury number is 27-F458527. A site I have had good luck finding gaskets is called the Shad Connection however there site is not loading tonight. I would pull the head cover off and see what kind of damage you can see. If the pistons are scored or damaged or the cylinders are scored I would agree with your first post about it being an anchor. If the piston and the cylinder look good maybe a head gasket is all you need.

 

[gregory62]

Re: 20 hp chrysler no high speed

I pulled the head gasket off last night and it was blown. The pistons and cylinders looked good<br />so all I have to do is find a head gasket. Also one of the screws has a crack in it. Are they special screws? Aluminum? should I replace all the screws, or just the one that is bad.<br />Thanks for all your help.

 

[eurolarva]

Re: 20 hp chrysler no high speed

That is good news gregory. You might want to go to www.chryslercrew.com and buy a downloadable parts manual for your motor. That will give you the chrysler part number for the head gasket so you can cross reference it to a newer availible head gasket. Check that screw with a magnet. I believe they are standard iron screws.

 

[gregory62]

Re: 20 hp chrysler no high speed

Thank you for your help.<br />I found a gasket a will be buying new screws.<br />Hopefully that will be the end of the problems for a while.<br />Thank again<br />Greg