98 Evinrude E115SLECM Eventual Bog @ 5000 RPM

[c6mcfall]

I really had not used the boat for some time, still getting things sorted from Irma.. After Irma I replaced all the lines to the oil tank + new ball, screen, gaskets, new impeller, fuel filters & changed lower gear oil + decarb. Plugs looked OK, might have 75 hrs on them since last set. Little history, I’ve had this rig for 3 years now. I put all new coils, pack, wp, plugs, plug wires, fuel lines from tank to the internal fuel filter on the motor, primer bulb and new internal fuel filter when I got it. I usually change the external fuel filter every 6 months, cheap insurance + I can see what the fuel looks like. Motor has been solid for last 3 years.

Motor starts right up, idles fine. I have a long run (15 min) before I can get to place where I can fun it flat out. Run it up on plane, seemed to run fine. Then after a few min, could see the primer ball collapse and motor would obviously slow down. Tank on the boat is internal, though maybe vent clogged, pickup tube clogged, bad primer bulb, or anti-siphon valve?

What I Tried and Results so far:

• Removed fuel cap, same results.
• Pulled pickup tube (has screen) not clogged and seems fine (original)
• Anti-syphon valve, seems to work (original)
• Replaced Primer Bulb – Runs longer but eventually starts to bog. (tested with fuel cap off, no difference) It does NOT appear to be collapsing but If I go and try to pump the bulb as it’s bogging it just collapses like it’s in a vacuum state

Boat runs fine below 5000 rpm’s, once I get 5000 RPM or over it’s a few minutes then starts to bog. I would have no issues replacing the pickup tube and anti-siphon valve either, just want to be sure I’m looking in the right area. I found it strange that I only have bogging at 5000+RPM’s, would fuel pump going bad cause the primer ball to collapse?

One other thing that was concerning me was the temp gauge. So before Irma my temp gauge started showing it running at idle over 140, closer to 170. On plane would be just above 140 F maybe 150-155?, so I replaced the WP. Still doing the same,at idle reads 172-174 F (analog gauges), but if I use a digital thermometer the heads read 142-152 depending on where I measured. This is me after a few hour run and a 15 min idle @ 1500 RPM back to the dock. On plane, the gauge is over the 140 mark, maybe 150-155?. Don't know if they are related just thought I should include it.

Thanks,
Fred

 

[racerone]

The bulb collapsing indicates there is a blockage in the fuel tank pick-up, anti siphon valve or line between the bulb and fuel supply.--Or a venting problem.---------Easy to test run with a portable tank and hose.----That would prove a blockage exists..

 

[c6mcfall]

Thanks, that's what I thought too, kicking myself for not bringing a tank. I'll give that a shot next weekend and report back

Any advice on the heat question?

 

[oldboat1]

I sounds to me like the gauge may be an issue (IR test pretty dependable). Might need to replace the sender, or just clean up the wiring.

 

[jakedaawg]

Did this boat go swimming in the hurricane?

 

[c6mcfall]

Did this boat go swimming in the hurricane?

Thank God no it didn't! Was secured to a lift but was floating, we had 4+ feet of water, over our bulkhead.

As for the sender, can that be tested? Should I pull it and clean it?

 

[oldboat1]

I would try cleaning first -- make sure connections are shiny (gauge too).

[edit. sensor has a pigtail and plug attached, doesn't it? would pull it apart and use some electrical cleaner.]