cooling issue with 9.9

I recently bought a 1978 johnson, the previous said had water impeller replaced last yr. the motor runs fine but it takes at least a min. or longer b4 any water comes out of the pisser, once it starts it comes out real hot at first then it cools off after a min. or so. the water pump seems to pump good once it starts pumping. is this a bad thermostat or water pump? thanks.

Re: cooling issue with 9.9

Don't ever believe anything a seller tells you. Pull the G/C and check the water pump. Then if needed go after the thermostat.

Re: cooling issue with 9.9

If it does that consistantly, I would guess that the thermostat is the problem. You could just remove it, replace the cover and see if you have a steady stream. Then replace it with a new one, if needed.

However, Its always prudent to check the condition of the water pump/impeller when you have a cooling problem.

Re: cooling issue with 9.9

I went over his house last night, he gave me the bill from the repair shop dated 6/20/2012, for impeller and lower seals, 250.00

Re: cooling issue with 9.9

upper water tube grommet partially collapsing could yield these symptoms as well...requires pulling the powerhead to replace,but you could also check/replace the thermostat at that time as well as any other gaskets that might be suspect...head, exhaust gaskets, water cover gaskets,etc...if you decide to check the thermostat it's located in a "mean spot to get to < bottom of the water cover > ..if you haven't found it already go to leeroysramblings.com..9.9/15 hp. maintenance and repair for more info

Re: cooling issue with 9.9

ok, I decided to check the impeller, pulled lower, the impeller looks new, not hard not cracked, I put it back together and tested, I get water out of the pee hole ok, there are two holes in back of the leg that are supposed to be exhaust reliefs, I get water out sometimes and sometimes steam, is this normal? I am running it on muffs with very cold water here in mi. seems to me it"s still running to hot.

Re: cooling issue with 9.9

When it is running can you lay your hand for over about a minute on the block behind the flywheel? IT WILL GET HOT, as most thermostats are somewhere between 140 & 165 degrees, but if the paint starts burning then something is wrong.

It could be anywhere in the water system from impeller, swolen water tube grommet at the powerhead, corrosion inside the water jackets, a stuck closed thermostat OR even a swolen/restricted outlet grommet at the powerhead.

Personally I would first pull the head, which will allow you to inspect the water jacket passages around the cylinder walls AND while it is off pull the thermostat cover. If there is any debris inside any of these passages, clean them. Put the thermostat in a pan of boiling water & look to see if it is opening/closing when hot/cold.

Yes, you may well get some water & steam out those 2 holes in the upper exhaust housing.

Re: cooling issue with 9.9

this morning I put in my big tank, now it"s pumping good, all kinds of water out of those 2 holes, funny how it wouldn"t pump good on the muffs, thanks for the advise.

Re: cooling issue with 9.9

i have a 1994 and it does the same thing, i think the pump likes to be submerged

Re: cooling issue with 9.9

I found out one thing years ago and I got burned. Don't try to trouble shoot a cooling problem on a flusher. Put it in a test tank or the lake.

Re: cooling issue with 9.9

boobie said:

I found out one thing years ago and I got burned. Don't try to trouble shoot a cooling problem on a flusher. Put it in a test tank or the lake.

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Absolutely. You can work on just about anything else, but not a cooling problem. Totally agree.