Chrysler 360 RPM problem

"I was wondering if anyone can

"I was wondering if anyone can help me out? I have twin 360’s. One engine runs fine but the other engine has problems getting the RPM’s out of it under a load. You can sit at the dock rev both engine up & you can get the RPM’s up to about 4 Grand. Once you put it under a load you can not get one engine past 3 Grand. I was given this boat from my Dad & the following are a few things he has done to them.

- Re-built both engine’s

- New carburetors

- New electric fuel pumps

- New caps & rotors

- New fuel separators



We are going to check the props out to make sure they have the correct pitch on them. Any suggestions would be greatly appreciated.


Thanks,"

"I went through a similar issu

"I went through a similar issue last season with a Chrysler 318. There are a lot of factors that affect performance. You need to start eliminating them one at a time. An easy thing to verify is that the spark is advancing. Put a timing light on the engine. Observe the timing, starting with the engine at idle, and reving to 2500 rpm without load, you should see the spark advance about 20-25 degrees. If it does not advance, carefully examine the springs & counter-weights in the distributor. As rpm increases centrifugal weights in the distributor advance the spark and are resisted by counter-balance springs. The weights get sticky and springs get corroded. An ignition shop can *re-curve* the distributor if the advance is not working. Back-firing is another symptom of spark advance trouble.

Have you checked the compression? That seems a more likely culprit than the prop, especially if one engine is running good, they are likely the same size unless somthing silly happened...

Another thing to check is if the choke is opening all the way. It should be straight vertical when the engine if warm. If the throttle plate is partially tilted, you won't get full airflow at the high end. The choke linkage can get sticky and the coil can get tired.

In my case, I re-curved the distributor and had the carburetor re-built. Both fixes were necessary, and I got back to 4000 RPM at WOT. My engine was an '86, and hadn't gotten a lot of attention from the prior owner.
Good Luck!
Chuck"

"When your mechanic replaced a

"When your mechanic replaced all that did he retime the engine?
I had a simular problem. Turned out the little tab used as a timing mark was labeled wrong and before was actually after and after was actually before. I was running 7 degrees ATDC rather than 7 degrees BTDC. The enging was a rebuilt job and the tab was for a different rotation. Two years it took me to find it and alot of headache. and $$$ spent.
Morale of the story. Check your timing and Check your advance. Dont just set the number one cylinder where the tab says and assssume it is right. Mine had the same problems yours did identically!
And when you fix it, come back here and let us know so others can learn from your trouble."

I have twin 360 chryslers with

I have twin 360 chryslers with a similar problem. I could only get about 2500 rpm out of the port motor under load. I disconnected the tachometer wire at the coil and the boat ran fine. It appears that there was a short somewhere in the wiring or a problem with the tachs themselves. Try this simple fix before you spend any more money. I learned the hard way.