Quick question for the board: we have a 19 foot Triumph equipped with a 90 HP Johnson outboard, of 2005 vintage, which ran like a top for the '05 and '06 summers.
Unfortunately, last season ('07) it began having issues which persist to this summer. Namely, the overheat light coming on at startup.
Symptoms as follows:
* "Hot" light and warning siren (~60 seconds) come on after 1-3 minutes of idle or slightly above speed
* Oil level is adequate
* "Hot" light is activated whether or not the engine is allowed to warm for 30 seconds or 10 minutes
* After "Hot" light, attempts to throttle up induce prop cavitation
* However, after cavitation is induced, if engine is shut off for 30 seconds or more and restarted, it performs normally with no cavitation or "Hot" warning light
* Engine is able to "pee" normally
* Offseason storage/service had a look and informed us that it was caused by a clogging of the intake down close to the prop that also measures speed
* After clearing this, however, condition persists
As a result, I have several questions:
* First, and most obvious: anyone have an idea what the problem is?
* If so, how can it be addressed?
* Does it require servicing? (and what do I tell the servicing personnel to check?)
* Or is it something that can be fixed outside of a shop?
Any and all help much appreciated. I've hunted through the forums and other sites and found suggestions that similar conditions could be caused by:
* Unclean carbs
* Incorrect spark plugs
* Malfunctioning VRO oil pump
* Condensation in the VRO oil pump
* Pinched oil or gas lines
* Worn impellers for the water pumps
etc
But I can't determine which, if any, of those suggestions is the likely cause, and based on that how I should proceed.
Unfortunately, last season ('07) it began having issues which persist to this summer. Namely, the overheat light coming on at startup.
Symptoms as follows:
* "Hot" light and warning siren (~60 seconds) come on after 1-3 minutes of idle or slightly above speed
* Oil level is adequate
* "Hot" light is activated whether or not the engine is allowed to warm for 30 seconds or 10 minutes
* After "Hot" light, attempts to throttle up induce prop cavitation
* However, after cavitation is induced, if engine is shut off for 30 seconds or more and restarted, it performs normally with no cavitation or "Hot" warning light
* Engine is able to "pee" normally
* Offseason storage/service had a look and informed us that it was caused by a clogging of the intake down close to the prop that also measures speed
* After clearing this, however, condition persists
As a result, I have several questions:
* First, and most obvious: anyone have an idea what the problem is?
* If so, how can it be addressed?
* Does it require servicing? (and what do I tell the servicing personnel to check?)
* Or is it something that can be fixed outside of a shop?
Any and all help much appreciated. I've hunted through the forums and other sites and found suggestions that similar conditions could be caused by:
* Unclean carbs
* Incorrect spark plugs
* Malfunctioning VRO oil pump
* Condensation in the VRO oil pump
* Pinched oil or gas lines
* Worn impellers for the water pumps
etc
But I can't determine which, if any, of those suggestions is the likely cause, and based on that how I should proceed.