Engine RPM cycling-gctid363602

[seychellois_lib]

Took the boat (1993 3288 twin Hino 150s) out today after several month winter downtime. Ran the engines up to 2300 RPM and noted the port engine would cycle down to 2000 RPM then return to 2300 then back down to 2000. Starboard engine running no issues. When engines throttled back to 2000 RPM no issue. Both engines running solid at 2000 RPM. Any idea what may be going on? Fuel supply comes to mind (filters, fuel contamination etc.) any other thoughts before I start troubleshooting?

Thanks

Mike

[Guest]

Change the fuel filters.

[mmichellich]

First thing to check are primary fuel filters. That is how the engines react to a partially blocked filter. At least that is cheapest of several alternatives.

[seychellois_lib]

Thanks guys. I'll take a look at the fuel filters as a first step.

Mike

[seychellois_lib]

That was the problem. The primaries were badly fouled. Port worse than starboard. We eventually lost the port engine altogether. I replaced both filters yeaterday after cleaning the water reservoirs. I'll need to keep an eye on them to confirm this was simply a long term accumulation of gunk in the filters vice a more significant fouling problem in the tanks.

I have absolutely no excuse. I knew better. I should have changed these out after buying the boat some time ago but have been putting it off etc. etc.

In any event, got excellent training on the fuel system as a result so it wasn't a complete waste.

[mmichellich]

seychellois_lib wrote:
That was the problem. The primaries were badly fouled. Port worse than starboard. We eventually lost the port engine altogether. I replaced both filters yeaterday after cleaning the water reservoirs. I'll need to keep an eye on them to confirm this was simply a long term accumulation of gunk in the filters vice a more significant fouling problem in the tanks.

I have absolutely no excuse. I knew better. I should have changed these out after buying the boat some time ago but have been putting it off etc. etc.

In any event, got excellent training on the fuel system as a result so it wasn't a complete waste.

Do like the rest of us and carry several spare filters for each engine and gen set.