1962 3100 seabreeze engine question

[johnandshellie]

Hello,
I have a 1962 3100 seabreeze I am running into a problem with the port engine. It runs for about 30 minutes then loses power, I have changed the impeller, did a full tune up with coil. it seems to run hotter then the starboard engine. We have been working thru the systems but I am coming up at a loss as why it is losing power after it heats up. Any idea or suggestion are appreciated
thanks in advance
John

[P-Dogg]

Does it reach top rpm in neutral, but not under load? Boat been sitting? What does full tune up mean to you?

The more detail you can provide, the more likely you will get a diagnosis rather than an RP.

One of my crusaders had similar symptoms. Turned out to be weak mechanical advance springs.

[johnandshellie]

Does it reach top rpm in neutral, but not under load? Boat been sitting? What does full tune up mean to you?

The more detail you can provide, the more likely you will get a diagnosis rather than an RP.

One of my crusaders had similar symptoms. Turned out to be weak mechanical advance springs.

It does reach top RPM in neutral and it only has the power loss after 30 minutes of running. Tune up was new plugs, cap, rotor, points, condensor, plug wires and coil. I had thought it was the impeller, because the motor run hotter that the starboard side, but we changed that out yesterday and the old one still had a couple of years left on it. The boat was sitting for several years, however, we have been running it on short jaunts all summer.

Yesterday I got almost 45 minutes of run time at 2200 rpm before it lost power and died. it seems that when I let the motor cool off for a short time it runs ok until it gets hot again.

[oil&water]

Does it reach top rpm in neutral, but not under load? Boat been sitting? What does full tune up mean to you?

The more detail you can provide, the more likely you will get a diagnosis rather than an RP.

One of my crusaders had similar symptoms. Turned out to be weak mechanical advance springs.

It does reach top RPM in neutral and it only has the power loss after 30 minutes of running. Tune up was new plugs, cap, rotor, points, condensor, plug wires and coil. I had thought it was the impeller, because the motor run hotter that the starboard side, but we changed that out yesterday and the old one still had a couple of years left on it. The boat was sitting for several years, however, we have been running it on short jaunts all summer.

Yesterday I got almost 45 minutes of run time at 2200 rpm before it lost power and died. it seems that when I let the motor cool off for a short time it runs ok until it gets hot again.

Did the engine do the same thing before tune up?

[johnandshellie]

I believe it did, I had it serviced by White Marine in Portland, OR.

The weird thing is it runs for abut 30 to 45 minutes before the power loss manifests itself. I am thinking on trying to change out the thermostats next.

Did the engine do the same thing before tune up?[/quote]

[oil&water]

Does it sputter like a loss in fuel or just cut off?

[johnandshellie]

It does do that, I have a new fuel pump to try next. the starboard engine had fuel problems but it would not run until I put the new pump in.

been thinking it could be a vapor lock but not sure how to solve that issue. The fuel lines are above the engine.

Does it sputter like a loss in fuel or just cut off?

[P-Dogg]

Swap the fuel supplies to the engines. Its free, and will tell you if culprit is fuel related. I'm thinking anti siphon valve if your problem moves to the other engine.

In my loss of power incident, swapping fuel lines didn't help, so not fuel related.

Right after my power loss, i could reach wot in neutral if I dared, but in gear, no dice. As I said, that was fixed by replacing distributor springs.

[johnandshellie]

Swap the fuel supplies to the engines. Its free, and will tell you if culprit is fuel related. I'm thinking anti siphon valve if your problem moves to the other engine.

In my loss of power incident, swapping fuel lines didn't help, so not fuel related.

Right after my power loss, i could reach wot in neutral if I dared, but in gear, no dice. As I said, that was fixed by replacing distributor springs.

Unfortunately I cannot switch lines as they are too far apart. i could be done but I would have to by extension hoses.

[oldboat1]

Do you use water separating filters? If not, can check for water by siphoning a bit up from the bottom of the tank, and letting it settle out in a glass jar. Fuel will float on top of any water.

How hot is it getting? Able to hold your hand on the risers when it's acting up? An infrared heat gun is an excellent tool to have aboard. If nothing else, gives you a baseline.

[johnandshellie]

Do you use water separating filters? If not, can check for water by siphoning a bit up from the bottom of the tank, and letting it settle out in a glass jar. Fuel will float on top of any water.

How hot is it getting? Able to hold your hand on the risers when it's acting up? An infrared heat gun is an excellent tool to have aboard. If nothing else, gives you a baseline.

Yes we have changed the water separating filters several times, the port engine is running much hotter than the starboard engine. I'm going to try the thermostats on it next.

[WayWeGo]

If the engines are running on different fuel tanks, maybe you have a clogged vent for the tank and are developing a vacuum in the tank.