I am brand new to marine engines, and am by no means qualified to tinker with them. Still, I enjoy learning, am willing to get my hands dirty, and have some problems I need to resolve.
I bought an older boat. It has a 4 cylinder 224ci/3.7l 1985 Mercruiser rated at 170 hp. Boat ran OK when I first took it out. Starting was a bit tricky, but only because depressing the "throttle only" button required a good thump from the side of my (now bruised) fist. I've temporarily solved that problem while I think of a better solution... Only other issue was that opening the throttle wide open from low 1,000 RPM caused significant hesitation or the engine just cut out. Able to hit 35mph at 4,300 RPM WOT. No idea whether that's acceptable. 19ft bow rider, very calm conditions, 21p lightly damaged prop.
The real problems kicked in on boat ride two. Went for a 2 and a half hour ride on the river. Boat ran fine (same hesitation issue). Then, halfway home, it started to surge/hesitate at about 3,000 RPM and finally died. Tried starting it for about 3 minutes. Gave up for 10 minutes. Got it started. Ran it in neutral at 2,000 RPM for 3 minutes. Put it in gear. It died. Repeated three or four times. Got boat to move. After some exciting lock/barge traffic/starting troubles, got the boat back on the trailer and opened the drain plug. Lots of water, at least two or three gallons (plug did not get pulled after the first outing). Noticed some coolant content in the water coming out of the drain plug.
Seller provided new (needed) distributor cap. Cap replaced, timing adjusted to 6 BTDC.
Round three. All day on the lake. Boat ran OK for most of the day (2 hours skiing/tubing, 1 hour off, 2 hours tubing/skiing, 2 hours off, 30 minutes tubing, skiing, 30 mins off, 2 hours skiing/tubing, 30 minutes off). Light hesitation when opening throttle wide, but easing it over 1,800 RPM and then opening it fully helped a lot. After the schedule of activity itemized above, took the boat out for skiing. Lots of hesitation, no power, full throttle was uncomfortably rough and couldn't beat 15 mph. Pulled the boat off the water, drained lots of water from bilge, noticed more coolant in water, put boat back into water. Still rough, still slow, still no power. Engine unpredictable had 10 - 15 second spurts of power, etc.
Refilled coolant after round 2 (river trip), estimate that I needed to put about half a gallon into the reservoir above the exhaust manifold. Filled it to about 1/2 inch below the top of the reservoir.
I am running compression tests tonight and will check how much coolant I lost at the lake.
Also noticed a 1/8 inch gap between the transom and the top of the stern drive transom plate. Could the water be getting in here? Will tightening the nuts on the bolts inside the transom close that gap?
Also noticed very damaged exhaust bellows between transom plate and bell housing. Will this help resolve any of these issues?
In general, please help. Any insights?
I bought an older boat. It has a 4 cylinder 224ci/3.7l 1985 Mercruiser rated at 170 hp. Boat ran OK when I first took it out. Starting was a bit tricky, but only because depressing the "throttle only" button required a good thump from the side of my (now bruised) fist. I've temporarily solved that problem while I think of a better solution... Only other issue was that opening the throttle wide open from low 1,000 RPM caused significant hesitation or the engine just cut out. Able to hit 35mph at 4,300 RPM WOT. No idea whether that's acceptable. 19ft bow rider, very calm conditions, 21p lightly damaged prop.
The real problems kicked in on boat ride two. Went for a 2 and a half hour ride on the river. Boat ran fine (same hesitation issue). Then, halfway home, it started to surge/hesitate at about 3,000 RPM and finally died. Tried starting it for about 3 minutes. Gave up for 10 minutes. Got it started. Ran it in neutral at 2,000 RPM for 3 minutes. Put it in gear. It died. Repeated three or four times. Got boat to move. After some exciting lock/barge traffic/starting troubles, got the boat back on the trailer and opened the drain plug. Lots of water, at least two or three gallons (plug did not get pulled after the first outing). Noticed some coolant content in the water coming out of the drain plug.
Seller provided new (needed) distributor cap. Cap replaced, timing adjusted to 6 BTDC.
Round three. All day on the lake. Boat ran OK for most of the day (2 hours skiing/tubing, 1 hour off, 2 hours tubing/skiing, 2 hours off, 30 minutes tubing, skiing, 30 mins off, 2 hours skiing/tubing, 30 minutes off). Light hesitation when opening throttle wide, but easing it over 1,800 RPM and then opening it fully helped a lot. After the schedule of activity itemized above, took the boat out for skiing. Lots of hesitation, no power, full throttle was uncomfortably rough and couldn't beat 15 mph. Pulled the boat off the water, drained lots of water from bilge, noticed more coolant in water, put boat back into water. Still rough, still slow, still no power. Engine unpredictable had 10 - 15 second spurts of power, etc.
Refilled coolant after round 2 (river trip), estimate that I needed to put about half a gallon into the reservoir above the exhaust manifold. Filled it to about 1/2 inch below the top of the reservoir.
I am running compression tests tonight and will check how much coolant I lost at the lake.
Also noticed a 1/8 inch gap between the transom and the top of the stern drive transom plate. Could the water be getting in here? Will tightening the nuts on the bolts inside the transom close that gap?
Also noticed very damaged exhaust bellows between transom plate and bell housing. Will this help resolve any of these issues?
In general, please help. Any insights?
