1973 9.8 water flow issue

[60sboater]

I replaced the impeller last fall and have run the engine in a barrel and on the river for about two hours total time on the new part. It flows a good stream but only at about 1,500rpm (approximation,no tach) and higher. At lower speeds the flow reduces to a sputter or just steam and the engine will get hot to the touch. Anyone have any insights on this?

 

[tpenfield]

Could be that the copper tube leading to the water inlet fitting inside the lower unit did not get properly mated when you put the lower unit back on. Otherwise, I would be considering internal restrictions. Near the 'pee hole' there is a plug that can be removed for back flushing the cooling system.

Should pee well at all rpm's . . . I actually reamed out the pee hole on my 7.5 hp as it continually clogged. Much better now.

 

[MTboatguy]

I had the problem on my '67, replaced the impeller, and only got a dribble, after searching all over the engine found out that mud wasps had plugged up the pee tube and it would only push enough water to keep cool, but wouldn't pee very good, so check the tube coming from the power head to the pee hole to see if it is not obstructed.

 

[60sboater]

I have not tried back flushing but will give it a shot. The copper tube seemed to engage the extension piece at the top of the w,p, cartridge w/o a problem. The hose from the PH connects to a plastic piece that pees the water out of the engine. That piece and the hose seem to be unobstructed. Thanks for the replies.

 

[Texasmark]

How deep is your engine when it is idling (deep enough to have several inches of water above the pump)? How hot is hot. If around 140 to 150 that's normal operating temp pretty much. OT sensors kick in at 195F. Your domestic hot water heater set on Normal is at 140F for a reference.

 

[racerone]

At the top of the water tube there is a plastic washer.------That has been known to melt and block waterflow to the powerhead.----Powerhead needs to be removed to inspect that.

 

[60sboater]

I need to check that washer and maybe pull the rear cover to look for silt. I don't think this one has a t-stat. Go too low on rpm and it stops peeing and the block gets hotter. It has several inches of water above the pump. Thanks.

 

[Sea Rider]

Disconnect hose, there should be a small diam peeing tube, if so, insert W40 red cannula fully in and squirt an overdose of the product and let soak. Poke in-out cannula severeal times before removing. If with small internal clogg product should take care, if not, you need a complete water passages clean out specially if engine has been used on salty waters and not conveniently flushed regularly after each outing.

Other nice flushing method is, if engine has a thermostat, remove it, connect a hose there and flush with house high water pressure for 10 minutes. Install therrmo back again and check if peeing has bettered.

Happy Boating