Over Heating

[sr79]

I changed 350/260 HP engine in my 79 Searay. Old engine had NGK BR6FS spark plugs, new engine came with NGK YR5 V Power spark plugs. New engine has a 145 degree thermostat but runs much hotter. My question is; do I have the right spark plugs? I've heard that spark plugs can make a difference in temperature and performance. What is the recommended spark for my engine?

 

[Bt Doctur]

MR43T asuming of course the new engine is a `79 . what kind of engine did you replace it with? the correct heat range is what really matters.

 

[alldodge]

I changed 350/260 HP engine in my 79 Searay. Old engine had NGK BR6FS spark plugs, new engine came with NGK YR5 V Power spark plugs. New engine has a 145 degree thermostat but runs much hotter. My question is; do I have the right spark plugs? I've heard that spark plugs can make a difference in temperature and performance. What is the recommended spark for my engine?

Agree with BTDoc and will add according to the cross reference both plugs listed above are crossed to MR43T
http://www.sparkplug-crossreference.com/convert/AC_DELCO/MR43T

 

[Ike-110722]

Agre with above but also make sure the plugs are the right length (inside the cylinder). You also may want to pull your thermostat and toss it into a pot of hot water to see if it is opening.

 

[NHGuy]

If you changed the engine but reused the peripherals you will want to go over the cooling system to figure out what happened. Did the previous engine fail from heat?