E
Ed Hogenboom
Guest
" I own a 1995 Mercruiser 7.4,
" I own a 1995 Mercruiser 7.4, with what is assumed to be a GEN IV engine block. I replaced the block recently with one that was supposed to be compatible according to the Dealer. The tag showed it to be a Mercruiser GEN VI. The installation revealed small differences such as bolt threads on the front of the engine to fasten pump& alt, oil pressure switch thread, timing chain cover as well as air intake manifold cover. The latter its heat shield cover bounced on the panel that holds the push rods. The GEN IV did not have such panel.I had to mock down the heat shield cover to fit the manifold on top of the engine with the correct torque rate.
The engine runs fine but...... oil pressure is high, RPM is 4000 i.o. 4400 before, some oil vapor gets into my carb (oil probably hotter than usual), and starting is excellent when cold, but difficult after shut down (sort of vapor lock).
Is this all due to incompatibility of the GEN IV vs VI? "
" I own a 1995 Mercruiser 7.4, with what is assumed to be a GEN IV engine block. I replaced the block recently with one that was supposed to be compatible according to the Dealer. The tag showed it to be a Mercruiser GEN VI. The installation revealed small differences such as bolt threads on the front of the engine to fasten pump& alt, oil pressure switch thread, timing chain cover as well as air intake manifold cover. The latter its heat shield cover bounced on the panel that holds the push rods. The GEN IV did not have such panel.I had to mock down the heat shield cover to fit the manifold on top of the engine with the correct torque rate.
The engine runs fine but...... oil pressure is high, RPM is 4000 i.o. 4400 before, some oil vapor gets into my carb (oil probably hotter than usual), and starting is excellent when cold, but difficult after shut down (sort of vapor lock).
Is this all due to incompatibility of the GEN IV vs VI? "