Katy Perry A4: you're hot then you're cold

[abudoggie]

Have a rebuilt Atomic 4 in a Pearson 28. Got it last summer. Purrs like a kitten. Last trip out we hit 190-200 on temp gauge. RWC. Smelled something like rubber burning. Also noticed a good deal of steam that wasn't present before. Spent the next day with my son checking under the hood. My exhaust riser has a t-injection fitting that injects from the top (similar to what our host offers). The exhaust hose from the injection t into the muffler was burned and leaking. It was actually charred at top under the hose clamps and crumbled when I removed it.

Thanks to the search function here I read some posts and figured I had reduced water flow. So today my son and I changed the impeller (spring clip wouldn't spring back had to persuade it with pliers). Pulled the thermostat. Replaced some suspect hoses. Then gave her an acid flush. Noticed when pumping in the acid water that the pump was hardly drawing water. Took much longer than usual to draw the 5 gallons. Let her sit 15 minutes. Fired up the motor. Son was monitoring exhaust water first exclaimed "yuck look at that mess!" Followed by "hey I think a lot more water is coming out". Hurray. Cranked fresh dock water through her for awhile. Steam gone. Good water flow.

But...now my temp is reading only 100? Is that from using dock hose water (probably pretty cool)?

Side note: found PO did not have a flange gasket off the exhaust manifold. He also didn't run an anti-siphon in the discharge hose loop. I ordered both from host and installed today. Also got the by-pass kit but will install it on the next trip. Thermostat looked ok. Will clean and test it.

Any thoughts on being too cool? 😀 Don't know what thermostat was in there but I think I should be running a 140?

In the meantime, I propose an official Afourian sing a long:
'Cause you're hot then you're cold
You're yes then you're no
You're in then you're out
You're up then you're down
You're wrong when it's right
It's black and it's white
We fight, we break up
We kiss, we make up
(You) You don't really wanna stay, no
(You) But you don't really wanna go-o
You're hot then you're cold
You're yes then you're no
You're in then you're out
You're up then you're down 😆

[Loki9]

The anti-siphon can't hurt, but probably isn't needed. If the water injection point is above the water line (as it is on the Pearson 30) then an anti-siphon is not needed.

[Trés 30]

Not sure what your water temp is this time of year, but maybe hotter plugs could keep your combustion clean if it's just too cold, and everything else is correct. Others here may have other, more precise input. Ed C recommended NGK XR4.

My nieces (and probably wife) would sing along w you
Welcome to the forum

[Mo]

I have RWC, no t-stat, by valve open 1/2 way, have been using NGK XR4 plugs for 5 years . The guage says 100 F. If you use a infra red gun you will find the head will be around 108 and the engine block will be around 142F...so it's fine. That block temp might go a tad bit higher after hours on end useage BUT not near danger mark.

My combustion chambers are always clean, haven't fouled a plug in 5 season and the same ones (same set of plugs) are still in use. Last week did a 6 day trip and covered 158 nautical miles. 16 hrs of engine useage and used 9 gallons of fuel...so I know I'm doing something right.

Keep an eye on your water flow next few outings to ensure there continues to be flow. If problems with steaming occur and reduced water flow occur there are generally three things I look at ;
1- T-stat
2- NPT fitting at output of exhaust manifold: where the hose attaches and sends water to hot exhaust...that can block at times.
3- Impeller, removed plate and ensure impeller intact, inplace, and no pieces missing that could end up in an elbow restricting flow.

[abudoggie]

Thanks for the follow up advice and tips. Really appreciate the community knowledge and helpfulness here.