Been on the boat on the little river again today, just by myself. Asked my missus, son, daughter, sister, friends, and a customer (whose car I still had in the yard) if they'd like to come for a ride on the boat but they were all either busy or didn't want to, I wanted to so went myself and had the radio for company.
Incidentally, pic of same customer's car I've done a bit of work on recently. He likes American cars and has quite a collection, mostly Hemi powered stuff but also some Ford stuff like this early 2000's Mustang. Loads of custom bits on the Mustang including engine bits such as cam, intake manifold. exhaust, shifter. etc. But he says the Mustang looks like a fast car, some of his other stuff is fast including his 1000bhp Jeep that I converted to LPG.
Back on the subject of the boat...
The relay I fitted (triggered by the purple wire from ignition, connects thick red wire battery power to the purple wire engine side of the relay) seems to have been a good idea, the coil is getting full battery voltage and there are no clicking noises from the VHF now, though I can still hear some alternator whine at low rpm sometimes.
The old thermostat I refitted seems to hold temp at 130/140F at and just above idle, around 150 at 30mph and 3000rpmm but still sometimes climbs past 170F at higher loads.
Dash temp reading fluctuates on the plane a little, say between 140 and 160 at 3000rpm but it seems it would run for hours like that with no problems
Flat out between 44 and 47 mph the temp reading sometimes climbs to 190+ and I've thought I could smell burning. Also flat out for more than say 1 minute the engine seems to start losing power. The temp reading, burning smell and drop in power prompted me to throttle back. A couple of times after giving it full throttle I stopped completely and could really smell burning, had a look at the engine and the lower end of the risers was too hot to touch but the higher end of the riser was normal temp.
Not sure what could be causing these symptoms, doubt it will be the thermostat, but over winter I'll rebuilt the raw water pump, rebuild the carb (already have the kit), maybe fit a new mechanical fuel pump, maybe fit a new thermostat housing, maybe pull the drive in case the seal on the water intake channel is compromised and causing it to be picking up some air.
Would appreciate any ideas regards the temp / burning smell issues.
Overall a good day on the river, but if the boat is supposed to be able to handle full throttle for extended periods I want it to be able to do that so want it fixed.
Thought occurred to install a GPS mph gauge on my phone on the ride back down the river today, seems the boat speedo is more accurate than I would've thought. Before I installed the app I had the boat speedo up to 47mph, after I installed the app I had the boat speedo up to 44mph and the GPS app agreed speed was 44mph. Speedo seems to over-read by 2mph at around 35mph.
Left the boat on a mooring on the river so will be visiting it at least once again over the next few days/week before bringing it home.