1999 c115 issues

[Brfyan1965]

I had wrote earlier about an alarm issue, I ended up changing the thermostat and the boat ran great for 2 days. Then the third day. It started having power issues at higher RPMS. I decided to chance spark. And had good spark on all cylinders. out of curiousity. i changed all 4 coils (since we had them) took it out today, ran great for about ten minutes, Then power issue resurfaced.

As you move the throttle up it seems to run good. Then it is like the throttle hits one spot. And its like it dies out. I can;’t get above 3500 RPM. It reminds o=me of a dead spot on an electric motor. When you hit a spot on the rheostat the motor loses its power.. If that helps explain any..I have No alarms. Any suggestions would be welcome..

[99yam40]

not enough fuel to hit higher RPM is my guess
fuel pump or sucking air in on the suction side of pump

[Brfyan1965]

I did have an air leak. When I replaced the fuel pick up line I could not get it turned completely and had to back off. I heard air leaking when I squeezed the pump. I tightened it (was able to turn that one turn) on the dock. And checked. We took it back out and it still failed. I ordered a new pump. It will be here tomorrow. The only other thing I have not done is rebuild the carbs.

[brian3006]

The only other thing I have not done is rebuild the carbs.

That would probably be your best starting point.

[Brfyan1965]

So I replaced the fuel pump. And rebuilt all the carbs. I took it out today. Definately runs smoother and reacted better. Ran for awhile then the alarm loss of power issue reared its ugly head back again. I ran good for awhile then sounded, I ran low RPMS for awhile. When the alarm shut off. I opened up again, this time ran for along time, Then I pulled the throttle back and turned around when I went back to full throttle for a small stints, then pulled back, then alarm went off again. I am at a loss.. (I already replaced thermostats and checked for good water flow. Before I had the loss of power because of an alarm issue)

[99yam40]

pull the stats and see if there is a bunch of stuff inside the passages or packed up against the stat
my brothers C60 has a bunch of stuff turning loose inside his cooling passages the get hung up against the stat restricting the flow

[Brfyan1965]

pull the stats and see if there is a bunch of stuff inside the passages or packed up against the stat
my brothers C60 has a bunch of stuff turning loose inside his cooling passages the get hung up against the stat restricting the flow

Yeah I did that. I replaced both stats when I had them out I sent water down each passage and made sure it went through.. I guess I could have sucked some stuff u I wil check again

[pstephens46]

Are you sure the alarm is for overheating? Assuming your guages are working properly?

[99yam40]

high RPM shoves a lot more water thru the motor and picks up stuff from down in the bottom of cavities, so you should check again to see

[Brfyan1965]

Are you sure the alarm is for overheating? Assuming your guages are working properly?

no I am not sure. I am not sure what other alarms could be. I know I have a few gauges off. I have some work to do on boat but want to get motor working first we are supposed to take it on vacation the third week of july so are getting worried

[Brfyan1965]

Update - I rebuilt the carbs and installed fuel lines and connections. The boat finally ran great, but then the high temp alarm came back on. I ended up removing the heads, there was a coating of salt. I cleaned all te salt. Then ran no salt. Have now ran the engine a few days with no alarm or power issues. I did end up changing the voltmeter, it now is working, I replaced the tach (i had a tach issue. It is showing proper idle speed. But when it gets above 2000 RPM it drops to zero and will not go back up until I slow down enough. I checked wiring and do not see anything I assume I got a bad tach (the one I replaced worked but it seemed to be running high (idle was showing as 1300 to 1500 RPM which was not correct. I also got a trim gauge and it just needs adjusted, I will read up on this.. Hopefully I can at least relax now as we go to Michigan in two weeks.