Mercruiser 170 will not exceed 2000rpm's

[bobrinne]

My 1985 Mercruier 170 starts and idles well. It will increase rpms easily to about 1200, then struggles to eventually reach 2000 rpm's. I put new points, condensor and rotor in. Gap was set at.018". We reset it to .021" and saw the rpm's increase from a max of 1600 to a max of 2000. The engine does not appear to miss at any rpms. At full throttle the engine just maintains 2000 rpm. Manually opening the throttle has no effect. All 4 plugs appear to be participating. The boat sat idle for 18 months. It was winterized by a trained mechanic when it was last run. The boat had 1/4 tank of gas when stored and Stabil was added. I added 10 new gallons of gas before I ran it this year.

 

[Master mechanic]

Compression is what on a warm engine with all the plugs out and the throttle fully down ?

 

[guyjg]

Look at the mechanical advance under the points plate for rusted parts. PB Blaster will dissolve any rust...spray it and work the parts back and forth. Blow out the dirt and excess oil w/ compressed air. Put the gap back to .018" and set the timing advance for 6 Deg. BTDC.