Lack of power....weird one

[amarchil]

5.7l OMC Cobra (1989)<br /><br />Motor has always performed great until this happened. After cruising for an hour, shifted to neutral and motor stalled....no way to start it up. <br />So, I suspected the coil was the problem, since the next day (with a cold motor), it did start up. I proceeded to change coil, distributor cap, rotor, condensor. The timing, the gaps on points, everything is right on spec. Ohh, and the fuel filter is new since beginning of the season, and carb (4bbl) is in good condition.<br />Anyways, the engine started up GREAT with the work i did on it. Idles and purrs like a kitten. I can rev up the motor on neutral...sounds perfect.<br />Then i take it on the water for a test run...at low speed, runs perfect...but when i push the throttle down.....lack of power..the boat cant get planing like it used to. <br />Checked the fuel pressure at the carb...looked ok to me...so pump isnt the problem.<br />Any ideas on what else i should look for ?? Really strange that this problem happens just after doing some ignition work...hmmm

 

[The Marine Doctor]

Re: Lack of power....weird one

Maybe the Accel pump is not working properly?<br /><br />TMD

 

[Bondo]

Re: Lack of power....weird one

Water in the Fuel.....?????

 

[Mikedg]

Re: Lack of power....weird one

When you did the tune up did you check the timing advance? If the advance is hanging up the engine will not develop full power but will start and run fine until about mid throttle.

 

[amarchil]

Re: Lack of power....weird one

Ok...dont laugh now......there is a little J shaped strip of metal (often called a spring) that goes over the points in the distributor. This spring puts pressure on the points to keep them tight together......and i didnt put the stupid spring in <br />So, at low speeds, the engine was performing alright because the copper strip of metal was putting enough pressure on the points, but as soon as I opened up the throttle...the contact points were probably flopping around in the distributor, cause performance loss.<br />Anyways, im going to put that darn spring in saturday and will keep you posted.

 

[boat doc]

Re: Lack of power....weird one

I have to agree with Mikedg. Typically upper end problems are secondarys not opening on carb, advance springs broke, or hung in distributor, or even a crossed spark plug wire, broken down plug wire, cracked plug if you replaced them, wrong size plug, or fowled plugs. Usually with spark plug a wire problems you get some backfireing, or carb pop <br /><br />an easy way to check your timing without pulling apart your dist, again: Use a timing light, watch the timing mark on your ballancer, see if it advances. I almost always set timing on the top end.

 

[John Boelte]

Re: Lack of power....weird one

It is important to change the points and condenser as a set. Not sure why, but they like it that way...

 

[amarchil]

Re: Lack of power....weird one

Just to let you all know.....Engine power is back to normal.....It was the stupid little spring that puts tension on the points that was not put in...as described in my last post.<br /><br />Thank you all so much for your help