Mariner 45 hp telltale delay/weak

[eatropefish]

I have a Mariner 45 hp(ser.# ob297199) bought used. When I start the engine the telltale takes approx 15-30 seconds to start flowing water. At idle the stream is weak in my estimation and the water is hot. At higher rpm the stream looks stronger. I replaced the impeller when I took ownership of the boat and every year since. As of now I don't know the pressure. Could I have a restricted power head? What are your thoughts on backflushing thru the telltale with CLR? I have not used the water hose on the supply tube yet. Thanks for your time.

 

[WillyBWright]

Re: Mariner 45 hp telltale delay/weak

Remove the gearcase and blow backwards thru the telltale with compressed air. Failure to remove the gearcase might mean just bouncing the obstuction back until water starts pumping again resetting the blockage. You might consider replacing the whole water pump, not just the impeller.

 

[eatropefish]

Re: Mariner 45 hp telltale delay/weak

Roger that. I have the parts on the way. Curious about the CLR (Calcium Lime Rust) for cleaning the water passages. I rebuilt a buddy's Merc 35 hp and the white crusty build up was pretty thick. It could be there is a piece of rubber from an old impeller lodged somewhere. Thanks for your reply

 

[eatropefish]

Re: Mariner 45 hp telltale delay/weak

Ok riddle me this: I hooked up the water hose to the water inlet tube. I get good stream out the telltale but also alot of water is coming out around the exhaust tube. When I shut the water off there is gurgling noises coming from inside the exhaust housing(not the tube) and the water drains out. Me thinks the gasket between the lower power head and the exhaust housing is leaking. This would explain the delayed/weak stream. What say you??

 

[andy6374]

Re: Mariner 45 hp telltale delay/weak

If you powerhead base adapter gasket was shot then the motor probably would run like crap with the cowling on because exhaust gases would be getting mixed with the air intake thru the carbs.

On most motors there are set of exhaust relief ports on the back of the motor just below the cowling. When the water pressure isn't strong enough to push the water down the midsection and exhaust out the prop, it just goes thru this relief ports instead.This is probably what you are seeing.

 

[eatropefish]

Re: Mariner 45 hp telltale delay/weak

I think you are absolutely right. I looked at my seloc manual for cooling diagram and the v6 showed relief ports and cooling for the exhaust tube. I flashlighted the housing with water running and saw where the water was emitting. I put the new waterpump on (complete) and am satisfied with the amount and pressure of water out the telltale. Thanks so much for everyone's input.