2004 225 EFI poppet valve spring replacement.

[mdtritn21]

I replaced my poppet valve spring with the part number listed 64878 and it over heats because the poppet won't open all the time. The original was a thinner spring with less tension on it but it's not available anymore so what's the trick to get the new one to work. I read something about cutting the spring but don't know how much to cut off. Serial number is 1B009942 and spring party number is 64878.

[EuropeanAM]

Do NOT cut the spring.

Did you replace the diaphragm, poppet and grommet? Champher the fins of the poppet? If must slide in and out like BUTTER.

64878 is precisely the correct part number. DO NOT attempt to modify. Poppet is not supposed to begin opening until water pressure exceeds 6.5 psi, and would be fully open by WOT.

[mdtritn21]

Yes I did all that and installed a new spring. I wish I would have saved the original spring now but got a new spring so installed that. Just got another new spring that seems to be lighter and I'm going to install that over the week end. I have over 20 lb. wp at wot but I think I'm going to have a new pump installed next week and have the guy check for anything that might be stuck in the intakes and look at the impeller blade to see if they have a curve in them. I've cleaned them up to the pump housing with a hose hooked to the motor and found nothing. I'll champher the fins more than I did before as I remembered you saying it had to slide like butter and originally it had to be forced in and out so I filed the fins down maybe not enough.

[1ranger487vs]

Mine runs at 20 also. No problems

[EuropeanAM]

BTW... the "thinner spring that's not available anymore" comment is not based on fact. The part number has remained the same since the day your engine was born.

Now if you get into aftermarket stuff, all bets are off.

ANY time you are having overheating and or water flow or pressure problems, ALWAYS, ALWAYS start at the SOURCE: The Water Pump.

[mdtritn21]

All parts I have came in Mercury marine bags and were ordered from the same Mercury schematic drawing you have on your site. It's not worth saving a little money for after market parts in the long run. I always put in a water pump kit when I have it replaced not just an impellor.

[EuropeanAM]

All good info. WHEN did you last replace the water pump?